Typologically diverse, multi-lingual, information-seeking questions, with Jon Clark

Guest: Jon Clark
Hosts: Waleed Ammar, Matt Gardner

We invited Jon Clark from Google to talk about TyDi QA, a new question answering dataset, for this episode. The dataset contains information seeking questions in 11 languages that are typologically diverse, i.e., they differ from each other in terms of key structural and functional features. The questions in TyDiQA are information-seeking, like those in Natural Questions, which we discussed in the previous episode. In addition, TyDiQA also has questions collected in multiple languages using independent crowdsourcing pipelines, as opposed to some other multilingual QA datasets like XQuAD and MLQA where English data is translated into other languages. The dataset and the leaderboard can be accessed at https://ai.google.com/research/tydiqa.

Matt Gardner
00:00

Welcome to the NLP highlights podcast where we talk about interesting work in natural language processing. The hosts are Matt Gardner, Waleed Ammar and Pradeep Dasigi.

Matt Gardner
00:10

All right. Today our guest is Jon Clark, who is a research scientist at Google in Seattle. Jon, welcome to the program.

Jon Clark
00:16

Thanks for having me. I’m excited to be here.

Matt Gardner
00:18

Last episode we talked with Tom Kwiatkowski and Mike Collins about natural questions and today we wanted to talk about something that’s very related that more recently came out called TyDi QA and Jon, do you wanna give us a brief introduction to what this is?

Jon Clark
00:33

Yeah, so TyDi QA is a multilingual question answering dataset with two distinguishing characteristics. First, it’s questions are information seeking, meaning that the questions are written by people who want to know the answer but don’t know the answer yet. And second, the languages are typologically diverse from each other.

Matt Gardner
00:53

Yeah, so natural questions, I guess when you think of most reading comprehension or question answering datasets today, almost all of them are in English. So the SQuAD, the ones that I’ve been building, DROP, co-ref, ropes, newsQA, triviaQA, hotpotQA. You could go on and on and on. And very recently people have started thinking, Hey, we should be thinking about other languages too. And you’ve got your own take on this. So I guess the first question is why do we care about other languages? I mean, come on.

Jon Clark
01:26

Yeah. So first off, the idea of typological diversity comes from the notion of typology and linguistics. Languages express meaning in different ways, and typology categorizes these differences as structural and functional features. So for example, in English, if you have one book, you say book. If there’s two, you say books. We’ve added this tiny bit of morphology on the end, the S and so we say the English expresses the plural. Arabic is even more interesting. One book is kitab and many books is kitub, but if there’s two of something, there’s yet another specific form of the word, kitaban. Forgive me for my pronunciation. So we say the Arabic expresses not only the plural, but also the duel. So that’s one typological difference between English and Arabic. There’s all sorts of different typological features ranging from preferred word order to how morpho syntax and codes grammar to whether or not a language encodes gender.

Jon Clark
02:29

So that’s what typology is. Why should we care? I think this has a lot to do with a question you’ve been asking a lot recently. Matt, when will we know when our algorithms can really read and answer questions? My take on this is that even if we’re doing perfectly in English, we still wouldn’t be there. It’s entirely possible that we might design our models in a way that overfits the specifics of English. So I want to know can your model handle the non spacing issues in Tai? Can it cope with the rich morphology of Russian, the free word order of Japanese, the compounding in Finish. I really want to be able to study how modeling interacts with all of these and I believe that as a field, these are things we have to keep our eye on as we evolve our model architectures.

Matt Gardner
03:19

Yeah, I agree. That was, that was a really great articulation from a science perspective there are really compelling reasons to think about other languages because our assumptions about tokenization, about how we model attention between words and a transformer or whatever, like it’s not at all clear that any of these assumptions transfer to other languages. And so having datasets that push us on that are really important and you gave a good reason why. We should be clear to say that the even more obvious motivation that I was kind of joking about earlier is that people speak languages other than English, surprise. And especially like you work at Google and Google tries to serve lots and lots of people all over the world, including the majority of which don’t speak English. Right?

Jon Clark
04:03

Absolutely. And for me that is another big part of this. It’s about helping real people. These days you can ask a question to a voice assistant, you know, you can type your question into a search box or what have you. And as long as you speak English, you can kind of expect to get an answer. It works pretty well, but there’s 7,000 languages out there actively spoken. And so there’s a lot of languages where this just doesn’t work too well yet, and the idea behind TyDi QA really is that if we can develop models that generalize across many of these important typological features, then maybe we have a chance of making progress across many of these languages at once.

Matt Gardner
04:40

Okay, so say we want to build a multilingual typologically diverse dataset, how do you go about doing it?

Jon Clark
04:47

So the way we collected TyDi QA is to start from the very beginning at question elicitation. We did everything directly in each target language, so to inspire questions, we showed people an interesting passage from Wikipedia written in their native language and we then had them ask a question. Any question with two small provisos first the question can’t be answered by the prompt. And second you actually have to want to know the answer to the question. Maybe these things seem obvious, but it actually changes people’s behavior a fair bit to encourage them to ask something. That’s interesting. I see this as kind of similar to how your own curiosity might spawn questions about interesting things that you see just walking down the street. We encouraged our question writers to let their imaginations run. So does a passage about ice make you think about popsicles in the summer. We said, fine, great. Ask who invented popsicles. From there we run a Google search on each question we find the top ranked Wikipedia article in the target language and then our annotators comb through the entire Wikipedia article and try to find a passage to answer the question, if there is such passage, they mark it and then they’re also welcome to highlight and minimal answer if possible. This is kind of the part that you might imagine gets boldfaced when we’re showing this passage answer to some user.

Matt Gardner
06:09

So you said in there that getting people to ask questions that they actually want to know the answer to changes their behavior. Do you have any evidence for that? Like did you, did you try collecting things in different ways or is this just intuition?

Jon Clark
06:22

So we did several pilot studies when we were getting this thing off the ground and initially what we found is that people kind of fall into all sorts of degenerate modes of asking questions. First of all, they think that they should be asking questions to a conversational partner because this is perhaps something that we’re used to doing with our own lines of questioning. And second, they are likely to just ask the same templated questions over and over unless you tell them no, no. Ask me something that you’re curious about.

Matt Gardner
06:53

Yeah. So you said a conversational partner. Do you mean like you ask questions that depend on each other? Is that what you mean?

Jon Clark
06:59

Exactly. So something like, “what’s your favorite book” or “how are you doing today?” We explicitly did not want to focus on those sorts of questions.

Matt Gardner
07:08

Okay. Yeah, that was, that’s different than I expected. I was thinking you meant like sequential questions, but you mean like dichotic questions, things that have pronouns that refer to you or me or this kind of thing. Okay.

Waleed Ammar
07:19

This [is] actually related to some observation I had when talking to older people about like question answering systems they use like and things like Google home. The actually very often think that there’s a person who is answering the questions like they actually think there’s a human on the other end somehow. So I think that’s, this might relate somehow.

Jon Clark
07:42

Yeah, perhaps and honestly I would be perfectly happy if people were to begin thinking about question answering systems in this way. It would mean that we’ve advanced far enough that we can handle all sorts of different distributions of questions.

Matt Gardner
07:55

Yeah. And the other thing you mentioned about templated questions, yes, we definitely see that a lot. I’ve collected lots of different datasets and getting people to not just give you the same templates is hard and does I guess asking questions. If you say you want to know the answer, then probably yes. You’re not going to ask the same question over and over again with like small differences. But there, I guess there are other ways to do it too, but that one does sound like it would probably work. Yes.

Jon Clark
08:22

I think that helped a lot and the prompts also helped. If I just ask you right now, ask me 10 questions. You will almost certainly draw a blank, but if I give you some stimulus like you would see walking down the street, Oh, I wonder how tall that sort of tree will grow. I wonder what the name of that dog breed is. These natural things that you encounter in life. We’re hoping to kind of model as these prompts.

Matt Gardner
08:46

Great. Do you know what kind of questions this elicited,

Jon Clark
08:50

This elicited all types of questions. So first off we’re definitely going information seeking questions which are kind of inherently different than the reading comprehension setting. So for us the questions come first rather than the passage coming first. One thing that comes up is there are a fair number of factoid questions in the data to the degree that those are the sorts of questions that our people were interested in knowing about. But I’d also like to mention one other thing that only really soaked in for me once we were pretty deep in this project. And that’s that it’s not necessarily that some questions are hard and other questions are easy. For example, factoid questions, let’s say, or that some answer types are harder. It’s the some answer contexts are harder to match to questions than others. So certain categories of questions may tend to naturally require these sorts of complex mappings between the question and the answer.

Jon Clark
09:45

But it’s this more subtle relationship between the question and the answer that really makes information seeking questions. Interesting. So when I look at examples of SQuAD and TyDi QA, I tend to see a lot of exact or near word matches in SQuAD, sometimes with paraphrasing, but usually not much more than that. But in TyDi QA the matching goes beyond simple paraphrases. And I think this is one of the key advantages of information seeking questions that the task remains challenging in a good way, even for seemingly straightforward questions.

Matt Gardner
10:19

Great. Do you have some examples of the kind of mismatch that you’re thinking of here?

Jon Clark
10:25

So one of the examples I like to cite is kind of figure one from the SQuAD paper. I believe this one is about precipitation. They’re listing off the types of rain and sleet and hail and other such things. And if you look at the question that’s asked from this paragraph, it copy paste perhaps four or five different words from the paragraph and nestled neatly amongst those exact matches is the answer grapple? Is this other type of precipitation that the question asker is interested in TyDI QA our relationships between the question and the answer are more subtle. So there’s this question where somebody asks in TyDi QA, we see questions that are a bit more subtle. So one of our annotators asks, “what ship did Han solo pilot?” And the answer does have one exact match, which is “Han solo” but this is maybe like halfway through the answer passage. The other matches are all not exact. So ship is not ship it Starship and pilot is not pilot it’s instead commanded. So there are more paraphrases there. And then the actual answer, the millennium Falcon isn’t even in the same sentence as most of these matches, it’s a sentence away. So there is a lot more indirect matching that needs to be done to properly answer these questions.

Matt Gardner
11:56

Can you read that paragraph or at least the relevant sentences?

Jon Clark
11:59

So the answer paragraph is “The Millennium Falcon is a fictional Starship in the Star Wars franchise. The modified YT 1300 Karelian light Frater is primarily commanded by Kirlian smuggler, Han solo; Harrison Ford” and it goes on.

Matt Gardner
12:17

Interesting. Yeah, that’s really cool. When I, when I think of these data sets I’d like to think of like what kind of phenomena do you need to answer the question? Do you need to understand in order to answer the questions here and from what you just read and the question that you gave, it looks like to me to answer that question, what you need is an understanding of co-ref and that’s a pretty hard co-reference problem. Perhaps this Millennium Falcon to the modified Y wing or whatever the phrase was. And then you need to know the predicate argument structure of the Y wing and that that local structure there that was primarily commanded by is a match for whatever the question was like what ship did Han solo fly something like this or what was he the pilot of? You have to know that these two argument structures are corresponding and so then you can pull out the modified thing and then you have to like use co-reference to go back to the name to get the Millennium Falcon.

Jon Clark
13:08

Absolutely, and by the way, this is just in the English case, like this is our baseline and then once you add multi-lingual on top of this with morphology and diacritics and other issues, frankly that’s where I think things become interesting.

Matt Gardner
13:24

Yeah, yeah, definitely. How are predicates argument structures realized and how is co-reference handled in various languages? These are very, very interesting questions. I agree. I guess a counterpoint to what I just said is that maybe, actually to get this question right, you just have to find Han Solo and find something that looks like the name of a ship and maybe my pre-trained embeddings already know this and so what would you say to this kind of response that are these questions really as hard as they look or are there cheap tricks to get the answers right?

Jon Clark
13:51

I think inevitably there are some cheap tricks that will help you solve many of these things, but in general, I think that when you’re looking over big passages like this, when you have to look over entire Wikipedia articles, you’re going to find that there’s a lot more distractors hidden in there. And that’s why it’s important not just to look at the passage, but to have to reason over entire articles because this is what real people want. I think if you have a real information need, I don’t want to give you a single passage and ask you to bold face the answer for me. I could have read that myself quite easily. I want you to do the hard job of reading over all these articles on my behalf.

Matt Gardner
14:33

Yeah, I think that’s totally fair. That’s how I think about things too. I focus more on the reading comprehension side where it’s like I want to like given a paragraph, see if the machine actually understands the paragraph in some way, but I agree that this is totally artificial, that if as a person, I have the paragraph in front of me, I’m not going to ask a machine, answer the question. I’m just going to read the paragraph and get the answer myself and so like it’s trying. I like the way you phrased this in your paper. I think Jordan Boyd-Graber also has talked about this, like there’s a difference between like information seeking versus validation and the reading comprehension setting, at least as I, as I think about it, is more about, let me validate the understanding of some system. Whereas what you’re targeting here is let me solve a human information need, which is definitely useful and interesting.

Matt Gardner
15:18

I do think it’s interesting though to think about when you have these human information needs, what kind of things do you need to do in order to actually fill the human information need? And maybe this is just because of whatever artifacts of the data collection process that you had. It does seem like the kinds of phenomena you need to understand are pretty similar, though harder than what you would see in SQuAD-1 in SQuAD-2. But the way I just for I think about this a lot, maybe I don’t explain it enough. The way I think about this is that SQuAD is basically predicate argument structure. I need to find a paraphrase of a question in the paragraph and maybe maybe there isn’t a paraphrase. That’s SQuAD-2. We need to figure out when there’s no paraphrase and then given this paraphrase, I need to extract some argument from the paraphrased part and maybe that paraphrase is very hard. Maybe it’s hard to realize that it’s not there that you can make this problem hard, but it’s still essentially a predicate argument structure matching and extraction problem. And I believe from what I’ve seen in the paper and from what you’re saying here that TyDi QA is basically looking at this same kind of problem. Do you think that’s fair?

Jon Clark
16:24

I think it’s fair to say that’s one category of problems you’ll see in there. I think that because we’ve collected this in an information seeking way, you kind of randomly get all sorts of different examples because you don’t know how the answer is going to relate to your question in advance, so I think there’s maybe some bias once you’ve looked at the paragraph to not be too harsh to this poor person who has to go answer your question later and so you’re looking for things like straightforward paraphrases. You’re looking for kind of a simple entity or argument that’s going to answer the question, but very often in some of the hardest questions that we’ve seen in TyDi QA and also the natural questions, there is no straightforward answer. One of the examples I remember from one of our training tasks back when we were still piloting is that there was this castle that was built, I don’t remember which one, but then it was destroyed by fire and then it was rebuilt and then it was expanded a bit and so when someone asks when was this castle built? They don’t know this whole story behind it. And so there’s also this notion of true ambiguity over different reasonable answers. And so you have to build a model that knows what is the preferred answer, what would the canonical most accepted thing be here.

Matt Gardner
17:46

Yeah, that’s a really great point. One thing that I find hard about information like that with all the caveats that I like this approach to pushing research and this is a really useful problem to be looking at. One thing that I find difficult here is understanding what it takes to solve the problem. When I construct a dataset that’s targeted at a particular phenomenon like temporal reasoning or co-reference resolution or whatever, I have a pretty firm understanding of if I can model these phenomenon correctly, I should be doing pretty well on this data. Whereas if I just do a blanket, hey users give me whatever and I’m going to pair stuff and just try to figure out how to answer these questions. I don’t really have a firm idea of how to make progress even and so like this is why I keep asking these like can you categorize things like have you done this? Like let me understand what’s inside this thing.

Jon Clark
18:38

So I agree that we really do need a good understanding of what it takes to solve these datasets and in some sense TyDi QA is aiming to do two things at the same time. We want to both be able to do the science and to be able to help the real users and so we stuck to this distribution. That’s interesting questions. I think how we’re going to need to proceed to really get farther into that is to begin taking slices of the data to find within this information seeking context, those questions that require paraphrase those questions that require co-reference for our various languages. We’re going to need the help of linguists, people that can gloss these examples and tell us this is an example of infects morphology in Arabic. This is an example of there being 200 different verb forms and Finish plus compounding, meaning that your model estimated this word piece very poorly. So I think we’re going to need to A. slice the data, but B. we’re going to need actual experts to help us do that and I’m hoping that these various subsections of the community, people who have been formally trained in linguistics can kind of partner with us to help us solve those problems.

Matt Gardner
19:51

Yeah, great. I agree and I think in the end we’re converging on basically the same thing because when you say I’m going to slice the data, maybe you find that there isn’t much, that there aren’t many examples of a particular slice and I might target some data collection to try to get more of them and now you’re taking basically exactly the same approach that I’ve been taking. It’s just starting from different places and ending up in the same place. I think we basically agree here.

Jon Clark
20:13

Indeed. I think there may always be some difference between the questions people want to answer and the questions that we find interesting though. So I do like the idea of first having some evidence that people would like an answer to this question before spending a lot of resources on finding out how we can make machines do that. I think the flip side of this coin is of course maybe people aren’t asking yet because they don’t trust our systems with this. They’ve tried a couple times and it didn’t go well and so they don’t ask again. So we should expect there to be some distribution shift in the future. Maybe it’s because we’re going to a different domain or because a different topic is suddenly of interest to the whole world and in those cases we would want our systems to already be prepared for things we haven’t seen yet. And I think that’s where preemptively looking at these slices would really come in handy.

Matt Gardner
21:09

I guess fundamentally though, there’s still gonna be a difference between information seeking and validation kinds of questions. Like there will be things that you would want to validate that you would never ask in an information seeking way. And so depending on, it just really depends on what’s your ultimate goal here.

Jon Clark
21:24

Absolutely.

Matt Gardner
21:25

And both are good goals.

Waleed Ammar
21:27

So while we talk about how the data’s collected. Could you comment on the differences in the collection strategy between TyDi QA and natural questions?

Jon Clark
21:36

So they’re very similar for answer labeling, we actually used exactly the same tool. The difference is really in where the questions come from for natural questions. These were real user queries that were heavily anonymized and that were common in the query stream. Among other constraints for TyDi QA. We actually elicited these questions. We showed people prompts, we asked them to generate questions that were interesting. And so this means the questions themselves look a bit different. But when you actually compare the distribution of our questions, personally I was pleased to see that these are basically questions that I think people would ask. I think that’s really the main difference.

Waleed Ammar
22:18

So I guess the baseline I would expect is like to start from where national questions was constructed. So what, why the division, what did he decide to do something different about the, the question collection?

Jon Clark
22:30

Well, I wanted something that would be kind of an even baseline across languages. And one issue that we know would be true is that again, users aren’t necessarily going to keep trying things if they don’t see great results already. And so for some of these languages like Swahili, I doubt there would be that many interesting and complex questions already there.

Waleed Ammar
22:55

Yeah, I would say this is also true for Arabic. I know for example, my grandparents, my parents are visiting these days and they find it really like surprising and like unimaginable to be asking questions at Google.

Jon Clark
23:09

Yeah. So I really see this data set is hopefully kind of paving the way to create something new that will then be able to help people later.

Matt Gardner
23:18

So you took, from a data collection perspective, you thought it was really important to start to do the process end-to-end in each individual language by itself. Like not starting from English and then translating. There have been another, there have been a number of recent efforts that went to the other way where they started with SQuAD or other datasets and translated them. Why take the approach that you took with TyDi QA?

Jon Clark
23:42

Yeah, so in many respects, using translation probably feels like the most natural way of getting a multilingual dataset. We have interesting English datasets. We have human translators available. Why not just pay them to translate into whatever language we’re interested in. So first there’s the issue of priming. If human translators are looking at the question and the answer at the same time, they’re more likely to reuse. Not only the same words has we kind of saw in the SQuAD case, but the same morpho syntactic forms in both the question and the answer. I’ve also seen examples where human translators keep the English word order when translating into a language that is usually free word order. If that happens, then our data wouldn’t really reflect the full richness of these languages and we could even kind of fool ourselves into thinking we’re doing a good job of modeling these languages when we’re really not there yet. And by the way, both in the machine translation community and even human translators are aware of this aspect of translated texts. They’ve named it translation ease. It’s so identifiable that people have even built high accuracy classifiers to distinguish original language text versus translated text.

Matt Gardner
24:55

And your history, I remember we were PhD students together at CMU. You did a lot of work on machine translation. So I assume your experience with all of this colored your motivations here.

Jon Clark
25:06

Absolutely. The other thing we’ve seen is that depending on translation direction, you kind of get the concepts that are centered around the source culture. So if we start from English, many topics in the dataset could be a product of western culture. The majority of Telugu speakers in India might not be terribly interested in American football. On the other hand, cricket might not come up so much in English. We even see this in our own data by the way. So like we had a Bengali speaker ask, “what does sapodilla tastes like”? This fruit does not sound terribly familiar to you. I know I had never heard of it before and that’s probably because it grows way more commonly in India than the US so we’re actually getting these topics that are more of interest for the target language.

Matt Gardner
25:56

You mentioned a few examples of different phenomena. You gave an example of Arabic and dual and plural. Do you have more examples of the kinds of difficulties that you would have in other languages?

Jon Clark
26:06

Yeah, absolutely. So one of the examples that I always like to talk about is this Finish question where somebody is asking “Who invented the seven day week?” and the answer in English is “The Babylonians most likely invented the seven day week.” In English. This is quite frankly a boring question, but then if you start looking at what’s going on in the actual Finish data that we collected, there’s these compounds. Different words are compounded in the question versus the answer, key words that you would actually want your QA system to match. Not only are they compounded they’re inflicted in various different forms, the answer itself of Babylonia is inflected in the elative case. This is something we’re not really so familiar with in English to inflect named entities. This is rather uncommon in Arabic we also have a lot of interesting examples. Script switching, sometimes diacritics are added or dropped, which is kind of unexpected. Usually diacritics in Arabic are reserved for very formal texts. But here we see that there are sometimes used for clarification in the questions. So all sorts of interesting things come up and we believe that many of these things would actually be an issue for our current state of the art models.

Matt Gardner
27:24

And so diacritics just for the listeners are things like accent marks, you might, that might be the most familiar use for English listening folks like an accent mark in Spanish or French, we don’t really have them so much in English. Sometimes you see two dots over a vowel in like highfalutin journalist text. We don’t really use this very much in English.

Jon Clark
27:43

Absolutely. So these would kind of look like diacritics in Spanish or other languages in Arabic they’re usually indicating short vowels which are spoken but not written down in the text.

Matt Gardner
27:55

And so you mentioned this Finish example of compounding and so in the paper your example has like day and week are in the same word in like the question and it’s like seven and day are in the same word in the answer or something like that’s like the grouping is different. I was thinking about certainly if you have a word level tokenization and you do like some kind of attention here, you’re going to have a hard time because there’s just so much morphologically that’s going on inside all of these tokens. But if I do a word piece tokenization, does this solve the problem?

Jon Clark
28:27

That’s a really great question. So we actually did run multi-lingual BERTs word piece around these things and frankly the result is not pretty. You do not get neatly segmented bits where you have the stem in one word piece and bits of morphology in another word piece. You say, fine, who cares if the word pieces really reflect what’s going on in linguistics? But it’s a bit worse than that still because the word pieces between the question and the answer look very different. You don’t get kind of the same boundaries, you’re not going to get exact match. So now you’re putting all the pressure on your neural model to hopefully map these things into a similar space. Maybe you get lucky on that or maybe if this is a rare concept or rare entity, your word pieces are not well estimated and things go poorly for you.

Matt Gardner
29:17

Yeah, it’s really interesting to think about this like the whole field has converged on BERT or Roberta or various transformers for like the last two years. This has been like almost everything uses these things and we don’t often stop to think about what the basic basic, fundamental assumptions about this model, what implications that has on like our ability to model stuff. We had a paper recently on modeling numbers like can you regress from the string like 1,223 can you take that string value and regressed to its numerical value and it turns out that using word pieces hurts you here quite a bit. Whereas like a character level, cnn will let you do this almost with like randomly initialized weights you can do this regression, but a word piece tokenization makes it very hard to do this. And this is just one example, even in English where this is a problem, but like when you go to other languages that have much more rich morphology, like we really need to rethink this. It’s kind of not such a good thing that we have this like monoculture on just using BERT or like these transformers that have particular underlying assumptions that just don’t hold up.

Jon Clark
30:23

By the way, I think there is another path here and it remains to be seen how things will actually go, but you could manually engineer decompounders, morphological analyzers, things like this, and I think that’s an interesting way to go. You could easily cover maybe the top 10 languages, maybe the top hundred languages with quite a lot of effort in this way. But I think if our goal is really to get to hundreds or even thousands of languages covered, I think we’ll need some sort of modeling approach that relies less on the supervised information sources and relies more on unsupervised methods to just figure out the structure of these languages. Otherwise we’re going to have a hard time finding our expert who knows machine learning and computer science and Khmer and specifically how Khmer is used in a social media context. So these manually engineered systems I think may get us some short term gains, but personally I would love to see more general methods that will get us farther down the tail quicker.

Matt Gardner
31:26

Yeah, I know that there’s been a lot of work over the years at Johns Hopkins on unsupervised morphological analysis. Like Jason Eisner and others have done a lot on this. I even had a conversation with a student that’s still pushing on this, which is really good. And yeah, like you, that work has been kind of on the sidelines. But when you think about the this TyDi QA and like what you actually need. If we really want to focus on these other languages, like as you say, we really need this kind of work.

Jon Clark
31:53

I think we do. And I would encourage everybody not to think of these as individual languages that we want to get good at, but to think of these languages as representatives of entire families of languages. So don’t just solve this for the one language. Let’s, really try to solve this thing in the general case.

Matt Gardner
32:11

Yeah. Great. So I guess on that note, how well do models actually solve this today?

Jon Clark
32:16

So in terms of absolute performance, the short answer is not very well. If you were to show the output to real humans, I doubt they would be very impressed. The good news for us researchers is we have lots of headroom somewhere in the neighborhood of about 15 to 20 points F1 on both our passage answer task and on this minimal answer task. And so that’s kind of the space between a multilingual BERT baseline and our current estimate of human performance. Maybe one quick note to make there is that we know our estimate of human performance is too low. So the natural questions was able to demonstrate that a 20 way human super annotator. So essentially you’re ensembling humans to help make your answer and then you evaluate that answer against five human annotators, your gold dev set. So that super annotator set up performs about 18 F1 better than a single human annotator guessing against those five gold references.

Jon Clark
33:19

So this is all to say that since TyDi QA only uses a single annotator to estimate our human performance, I’d actually expect there’s around another 10 or 20 F1 points of headroom even above our current human estimate. But I think we can cross that bridge when our models come to it. For now we have plenty to keep us busy.

Matt Gardner
33:38

And what about across languages? Do models do better on English than other languages? I assume that’s true.

Jon Clark
33:44

So to be honest, I think we can’t answer that question yet. So among the languages, the questions are different. The articles are very different. English has much longer articles than other languages. The answer content is often just not there in other languages, so maybe it’s easier to reason across shorter articles. Maybe we have more pre-training data in English than others, which is perhaps fair. Perhaps it’s just easy to guess null there’s no answer because often there’s not in some of these languages, so unfortunately I think 50 F1 means something different in each language.

Matt Gardner
34:25

And you said, so you put up a leaderboard for the test set and you said you did some interesting things there that you wanted to tell us about. Can you say what those were?

Jon Clark
34:34

Yeah, so I think it’s safe to say that there’s been a lot of discussion about the role of leader boards in our community, especially around whether they’re incentivizing people to blindly chase state-of-the-art numbers. Personally, I think of the numbers on leaderboards, like little existence proofs there exists some model architecture and some training regime that will result in this number on the test set. We’re hoping that leaderboards can give us a bit more than that though. We’re hoping they can also tell us more about the how and the why behind these systems, which is important if these leaderboard entries are going to help us with progressing science.

Jon Clark
35:10

So with this in mind, we’re asking folks to answer five questions along with their system submission. So maybe I can just kind of read those. “Is there a research paper describing your system?” “Is the source code available?” “Is the system trained on any additional public data?” Hopefully the answer to those three is, yes, “Give us a URL so that other people can better understand the meaning of this number on the leaderboard.” And then two more, “Is the system on any additional private data?” and “Is the system trained using any public APIs or private tools?” So hopefully the answer is no there because this means this thing is inherently kind of hard to reproduce. And maybe the biggest thing to point out about this is that a lot of folks are likely to be interested in using public translation APIs.

Jon Clark
35:59

So if you do that probably gets you quite far on the task. And that’s interesting as an existence proof. But by the same token, the output of the API may change next month. And also, I don’t know how much parallel data any one of these MT systems was trained on. So if you happen to have a billion sentences of Swahili, and I think you’re training on a million sentences in Swahili, this means I can’t really reason about how my system’s performance would generalize to Amharic or some other language that isn’t included in this set. So we ask these questions not as hard constraints so that we can still get the existence proofs, but to kind of also encourage good behavior and you know, note what it takes to do a correct apples to apples comparison with these numbers.

Matt Gardner
36:51

I noticed you didn’t have anything in there about computational resources.

Jon Clark
36:55

We don’t have anything in there about computational resources. I would hope people put these in their research papers. I think very often in the short term you can win big by using big computational resources, but in the longterm people become more and more mindful of these costs. As you kind of figure out that we’ve banked the gains, but now we would like to reduce costs. People become increasingly interested in very efficient methods and I hope that’ll just naturally come about as part of our iteration in the community.

Matt Gardner
37:29

Great. That I think is all the questions that I had. Is there anything you wanted to talk about that we didn’t cover or any final thoughts before we conclude?

Jon Clark
37:37

I guess I would just say a big thanks to the whole team that made this happen. We were lucky to have authors of several previous datasets including the natural questions and QuAC. We had linguists who are native speakers of Finnish and Russian. That was a huge help. We had folks that cared deeply about multi-lingual modeling and I also want to say a big thanks to everyone who takes up this dataset and your own research. We’re really excited to see where you take this.

Matt Gardner
37:59

Yeah, and I will add my final thought, which is I think this is great. I think thinking about all of the different linguistic phenomena that happened in language and like how different languages express things differently and how we need to be sure that our architecture assumptions are actually generalizable across languages. All of these things are excellent things to think about and it looks like you did a really great job in putting together a dataset that should be really useful for the community for a long time. So thanks.

Jon Clark
38:24

Yeah, thanks for having me on. I really enjoyed it.

Matt Gardner
38:26

Thanks. Thanks for coming on. It was nice talking to you. This is really interesting.