Docs: "must see"

[ethanachi]

An interesting border case happens here:

http://match.grew.fr/[email protected]&custom=5feef22b3ff08&eud=yes

where "must see" is pretty clearly a compound with an adjectival function, but the validator assumes that AUX (and specifically AUX) can never be in a compound...

My feeling is that the compound analysis is correct and the validator is making false assumptions, but curious as to others' opinions.

[nschneid]

Yeah I have noticed similar issues where a phrase with compositional structure is converted to an attributive modifier, like "make-or-break decision" and "easy-to-use tool"—should we recognize the internal structure reflecting the derivational origin of the expression, or just use compound across the board?

[nschneid]

Related: UniversalDependencies/docs#648, UniversalDependencies/docs#478, UniversalDependencies/docs#525

[dan-zeman]

Hmm, is it still AUX if it enters a compound? Isn't it VERB or something then?

[nschneid]

I think it's a compound in the sense that "church-going" is a compound in "he is a church-going person". But is compound intended for a narrower use of combining two words with like parts of speech?

[dan-zeman]

I don't think that the guidelines explicitly ban auxiliaries from the compound relation (although I did not check carefully now). I would expect auxiliaries to be more likely to participate in fixed than in compound (because they are function words) but _must see_ is obviously not what UD annotates as fixed. The reason why I made the validator report AUX-compound as an error was (if I recall it correctly) that some treebanks annotated light verbs as AUX, which is wrong.

Are there other compounds that contain auxiliaries? Or should we say that _must see_ is an English-specific exception?

[dan-zeman]

I transferred this issue to the docs repository because it has wider impact than just English EWT.

[nschneid]

Are there other compounds that contain auxiliaries? Or should we say that _must see_ is an English-specific exception?

Off the top of my head I can think of:

• a must-see television show
• a must-have book
  
  
  
  • ...this pattern feels productive: EWT contains a review with the preface "MUST READ"; it might be called a must-read review
  
  
• a can-do attitude
• a has-been celebrity
• a would-be student

To make matters worse, some of these MWEs can function as nouns:

• Those celebrities are has-beens
• Those books are must-haves

Not sure how to analyze those in UD.

[amir-zeldes]

Will post this also to the other issue, but for the record I think it's a normal compound with a phrasal modifier, in which all but the local head should keep their pos and deprel, so:

must/AUX <-aux- see/VERB <-compound- attractions

[amir-zeldes]

• a must-see television show
• Those celebrities are has-beens

I think it depends on tokenization. If they are hyphenated and left as single tokens, my preference would be to treat them as ADJ/amod and NOUN/root:

must-see/ADJ <-amod- shows
those <-det- has-beens/NOUN/root

Basically I'd try to punt this to morphology and say "this has some morphologically interesting internal structure, but UD syntax stops at the tokens" (after all, we don't analyze derivation deprels either).

[nschneid]

@amir-zeldes But what if they're not hyphenated?

[dan-zeman]

Is it a rule that they should be hyphenated in English? If it is, then goeswith might be an option.

[nschneid]

Some might prefer the hyphen, but it's not as obligatorily one word as "oversleep" or "anti-war"/"antiwar", where the first part is clearly a prefix so separating with a space is an error. From a COCA search, there are plenty of instances of "must haves", even in edited sources like magazines.

[ethanachi]

for what it's worth, this is an open class ("must-see", "must-have", "must-visit", "can-do") and is often found without spaces, so goeswith doesn't seem appropriate here.

I agree with @amir-zeldes' proposal, although "must-see" as a modifier seems looser than a normal compound, so it still seems best to analyze it as ADJ...

[amir-zeldes]

@amir-zeldes But what if they're not hyphenated?

If they're not hyphenated, I think there is a clear case where we retain the internal analysis, as in "must see movie", and a less clear case where I am more ambivalent, in which a categorical conversion results in the original governing POS being altered, as in the "has beens" case.

For "must see movie", I think the argument should hold that a. it is a nominal compound where the modifier happens to be a phrase, and b. it's a verbal structure "wrapped" in the modifier NP (the conversion). Because of this, I think the relationship between "see" and "must" is maintained, and I would do:

must/AUX <-aux- see/VERB <-compound- movie

For "has beens" it's a little more complicated, because a single word is doing "double duty" (a little like wh pronouns in free relatives). On the one hand, the morphological stem "been" preserves its verbal nature and takes a normal auxiliary "has". On the other hand, it has been converted into a noun and can now take an s-plural and fulfill an argument role. Our two options are then:

1. has <-aux- beens/NOUN/root
2. has <-compound- beens/NOUN/root

You can tag 'has' however you like, but I think morphosyntactically it's still AUX inside the compound, so I'd tag it as such (this is consistent with considering 'see' above to be a VERB). Between these two options, losing the internal function or the external function, I would prefer option 2., for two reasons:

1. We have good precedents for preferring external or "higher level" functions. Choosing compound is analogous to free relatives prioritizing the matrix clause function.
2. It's odd to have a NOUN with an aux dependent, and at least for me, less odd to have a morphological auxiliary serve as a compound modifier. In a meta-linguistic context, the latter should be possible anyway (we can say 'the "be conjugation" in Latvian')

[nschneid]

Option 2 seems a reasonable compromise (where the head needs to be a noun for external reasons), because the AUX tag preserves something about the internal derivation even though compound reflects the derived status. Based on the POS tags we can see it is a "special" kind of compound, and further analysis of the internal/external syntax such as with SUD could be added later. As long as the validator is willing to be flexible about POS tags of compound dependents.

(A small point: regarding

less odd to have a morphological auxiliary serve as a compound modifier. In a meta-linguistic context, the latter should be possible anyway (we can say 'the "be conjugation" in Latvian')

I'm not sure a metalinguistic use of "be" should remain AUX—if we're talking about the linguistic entity shouldn't it be NOUN?)

[dan-zeman]

I'm not sure a metalinguistic use of "be" should remain AUX—if we're talking about the linguistic entity shouldn't it be NOUN?

No. If a word is mentioned rather than used, it retains its dictionary POS category (see here). We could debate in this case whether it is AUX or VERB, but it is not NOUN.

In general, it looks like the validator cannot exclude AUX from the set of possible compound dependents. I will look into removing the restriction.

[Stormur]

Just chiming in: can't a productive construction like _must-VERB_ and all others of the same kind be analyzed just as an acl and its internal structure be left transparent as it is, i.e. with the VERB as its head? And this would be the same for _make or break_, while _easy to use_ would just be an ADJ plus its argument? The same for _church going_, where the word order is probably given by using a participial form instead of the "bare infinitive". In general, English appears to have this way of using verb phrases in an attributive function; no reasons for compounds here. In my opinion, orthographic conventions like hyphens do not seem to come in the way of such an analysis; they rather seem to be an aid for a correct reading. (Sorry if I was repeating some of the previous points.)

[nschneid]

There are a few matches to that analysis currently, e.g. "fly-by-night program": http://match.grew.fr/[email protected]&custom=5ff47e4953be0

Is there a good test for whether attributive modifiers behave like participial clauses or like compound modifiers? Maybe idiomatic ones like "fly-by-night" resist being moved after the noun or made predicative. But maybe we're just tempted to use the term "compound" because of the lexicalization of the expression and we should treat it instead like a more compositional phrase.

[dan-zeman]

As @amir-zeldes showed above, most of the examples in this thread do not need the compound relation with the auxiliary as the dependent. However, if the head acquires nominal morphology _(the celebrities are have beens),_ it cannot be tagged VERB any more. And as a NOUN, it should not have auxiliaries. (The validator would not flag them because they could legitimately occur in copular sentences such as _he has been a celebrity_; but this is a different case.)

[nschneid]

Right, I was wondering about the attachment of the idiomatic expression to its head noun outside the case where the verb is coerced to a noun and pluralized.

must/AUX <-aux- see/VERB <-compound- movie

Why compound and not acl?

[dan-zeman]

must/AUX <-aux- see/VERB <-compound- movie
Why compound and not acl?

My first pick would be acl here. But as a non-native speaker, I don't feel confident about the tests for compoundness in English.

[amir-zeldes]

I think my assumption that it's compound was mainly a knee-jerk reaction to it being a modifier on the left side of a noun in English, but I don't feel terrible about acl here, either. But then ideally all phrasal modifiers of nouns should be like that, no? Are there some cases where that doesn't work? For example, what if it's a PP like:

A by the book attitude

I think in this case acl would be wrong, no?

[nschneid]

Not sure why all phrasal modifiers of nouns should work like that. If in UD terms a PP is a nominal, then it's like a noun modifying a noun, the prototypical compound.

[amir-zeldes]

I think on some level both of these cases are "the same" - you're taking a complex phrase, which normally wouldn't pre-modify a noun, and wrapping it in something (which I initially interpreted to be an NP conversion) so it can serve as a modifier. So in phrasal terms, I thought we have:

(NP (NP (VP (must) (see))) movie)
(NP (NP (PP (by) (NP (the) (book)))) attitude)

I think coming from a Germanic linguistics perspective this is somewhat natural, since in languages like German, the commonality of these cases with regular compounds is a little more transparent. But in English you could indeed argue that these two are not the same construction, and the first one has a clausal modifier. Still, my gut feeling is that they are the same (maybe this is just a German-bias), and giving them different analyses obscures that. The basic structure of both is:

ANY-SYNTACTIC-THING-YOU-LIKE + NOUN

:)

[nschneid]

ANY-SYNTACTIC-THING-YOU-LIKE + NOUN

I can see an argument for an "attributive phrase" construction generalizing over amod, compound, nmod:poss, and maybe some other things. But I'm not sure UD's lexicocentric approach is suited to such generalizations.

Another complication that I realized is that prenominal participial forms tagged as VERB (PTB VBG, VBN) are analyzed as amod. If we were to attach _must-see_ as the acl of _movie_, why should the relation in _raiding forces_ or _foiled plot_ be amod rather than acl? Would _winning strategy_ and _award-winning strategy_ be treated differently?

[nschneid]

@lorislevin thinks these are all synthetic compounds, and per Bill Croft's interpretation of UD as a representation of information packaging, "must" in "must-see" is not packaged as an auxiliary nor is "award" in "award-winning" an object. She would just use compound.

[amir-zeldes]

Another complication that I realized is that prenominal participial forms tagged as VERB (PTB VBG, VBN) are analyzed as amod. If we were to attach must-see as the acl of movie, why should the relation in raiding forces or foiled plot be amod rather than acl? Would winning strategy and award-winning strategy be treated differently?

Ooh, yes, that would be bad. I much prefer for these -ing cases to be amod, since many are lexicalized into adjectives, and this way even if we quibble about POS, at least the syntax always has them as amod. I'm fine with compound for the phrasal modifier cases and amod for gerund modifiers, it will also keep things more in line with how it's done for German.