Lab 7 (due 2/19 11:59 pm)

Overview

The goals for this lab are to get non-verbal predicates working, to see what happens with non-verbal predicates with wh questions (but not necessarily get them working), and to keep making sure that MT works (now with the non-verbal predicates, unless transfer rules are required).

For tdl editing, please practice incremental development: Test as frequently as you possibly can, both by compiling the grammar and by testing specific sentences.

In general, this lab involves the following steps:

  1. Understand how non-verbal predicates work in your language.
  2. Build out your testsuite for non-verbal predicates.
  3. Ensure that your iso.txt file has translations for lines 15-17. (If you can't find these, please contact me for alternate plans.)
  4. Run your Lab 6 grammar over your initial testsuite.
  5. Extend your grammar (via tdl editing) to handle non-verbal predicates.
  6. Test your analysis with your testsuite.
  7. Test your analysis with the MT system (items 15-17 in eng.txt).
  8. See what happens with wh question in non-verbal predicate sentences.
  9. Run the testsuite and test corpus with the final version of your grammar.
  10. Write it all up.

Back to top

Build out your testsuite for non-verbal predicates

Can NPs, adjectives, or adpositional phrases function as predicates in your language? If so, do they require a copula in some or all cases? Does the form of the copula vary? Examples from English include:

Note that in some languages, the copula is required only in non-present tense, or only with NP predicates, etc. In other languages, there is not really a class of adjectives distinct from stative verbs. Or there maybe two classes of adjective-like predicates, those that pattern with intransitive verbs (or at least appear without the copula) and those that require a copula or are otherwise differentiated. Likewise, some languages don't really have PPs in this use, but rather use a locative verb together with an NP.

Construct relevant positive and negative examples illustrating how your language handles non-verbal predicates and add these to your testsuite.

Back to top

Non-verbal predicates

Background

The goal of this part of this lab is to extend the grammars to cover sentences where the main (semantic) predicate is not a verb, i.e., NP, PP, and AP predicates. In some languages (including English) such predicates require the "support" of a particular bleached verb (the copula, or perhaps a verb of location). In others, they can serve as predicates on their own. In still other languages, we find a mix: The copula (or other verb) is required for certain types of predicates or in certain tenses but not others. Or the copula (or other verb) is optional: possible but not required.

It's also possible that in some languages the copula is optional in matrix clauses but required in embedded clauses. I haven't found an example like this yet, but I'd be curious to know about it if you find one.

Note that in some languages, NPs inflected for locative case (or similar) function like locative PPs in other languages.

As you work on this, practice incremental development: You should be loading your grammar and checking that it compiles frequently. Similarly, as soon as you've put in enough to get one new sentences parsing, try testing that before going to the next sentence. Once the sentence parses, run your full testsuite before moving on. This practice will help you catch bugs early which makes them easier to find.


Adpositions

Some of your grammars have adpositions already, but few, if any, have semantically contentful adpositions. You'll need to define these for this lab. The matrix provides a type basic-int-mod-adposition-lex, which should have most of the information required. Define a subtype with appropriate constraints on the MOD and VAL values, and try it out to see what else you might need to add.


Copula (AP or PP or locative NP predicates)

We analyze copulas as semantically empty auxiliaries. You may already have a type very similar to this, perhaps from the adjectives library. The tdl for a copula should look something like this:

copula-verb-lex := verb-lex-supertype & trans-first-arg-raising-lex-item-2 &
  [ SYNSEM.LOCAL [ CAT.VAL [ SUBJ < #subj >,
                             COMPS < #comps >,
                             SPR < >,
                             SPEC < > ],
                   CONT.HOOK.XARG #xarg ],
    ARG-ST < #subj &
             [ LOCAL [ CONT.HOOK.INDEX #xarg,
                       CAT [ VAL [ SPR < >,
                                   COMPS < > ],
                             HEAD noun ] ] ],
             #comps &
             [ LOCAL.CAT [ VAL [ COMPS < > ],
                           HEAD +jp ] ] > ].

You may also need to create verb-lex-supertype which inherits from some of the types that your verb-lex type does, but not all of them. In particular, you want to get the types that give it access to whatever verbal morphology is relevant, as well as constraining it to be [HEAD verb].

The constraint [HEAD +jp] on the complement specifies that the complement should be (headed by) an adjective or an adposition. Depending on where copulas are required in your language, you might want to change this. If you need to give adjectives or adpositions non-empty SUBJ lists (e.g., because they can be stand-alone predicates in some cases; see below), then you'll also want to constrain the COMPS's SUBJ to be < [ ] > (aka cons) to make sure that the subject isn't realized twice.

Note that the copula verb uses the XARG to do the linking (the relevant constraint is declared on the supertype trans-first-arg-raising-lex-item in matrix.tdl). This means that the adjectives and adpositions will need to link their ARG1 to their XARG. This should already be the case, but you should double check.


Copula (non-locative NP predicates)

We will follow the ERG in positing a different copula for use with NP predicates. This is because we don't want to give every noun a semantic argument position for a potential subject. The copula verb for NP predicates will instead introduce an elementary predication linking its subject and complement.

This means that in many languages, this copula might just be an ordinary transitive verb. It's not in English, because it also has auxiliary properties. If the NP-predicate-supporting-copula in your language differs in its behavior from (other) transitive verbs, post to Canvas.

The PRED value for this verb should be "_be_v_id_rel".


Locative NPs

For languages that express meanings like in the park with locative NPs (i.e. no adposition), we will write a non-branching phrase structure rule that builds a PP out of locative case NP. You'll also need a lexical rule creating the right form of the NP and constraining it to be [CASE loc] (or whatever you called your locative case). This lexical rule should fit into the same position class as your other case lexical rules.

Here is a sample PP over NP rule, from the Marathi grammar from 2014. This rule uses C-CONT to introduce the locative relation.

Note that this rule builds PPs that can either be the complement of a copula or function as modifiers of verbal projections. Locative NPs as stand-alone predicates would need a non-empty SUBJ value, with an NP on it, whose INDEX is identified with #xarg and whose CASE value is constrained as appopriate. Similarly, if your locative NPs can't be adverbial modifiers, then the mother of this rule should have an empty MOD list.

locative-pp-phrase := unary-phrase &
[ SYNSEM [ NON-LOCAL #nl,
           LOCAL.CAT [ HEAD adp & [ MOD < [ LOCAL intersective-mod &
                                                    [ CAT.HEAD verb,
                                                      CONT.HOOK.INDEX #xarg ] ] > ],
		          VAL [ COMPS < >,
			        SUBJ < >, 
			        SPR < > ]]],
    C-CONT [ HOOK [ LTOP #ltop,
		    INDEX #index,
		    XARG #xarg ],
	  RELS.LIST < arg12-ev-relation &
		   [ PRED "_loc_p_rel",
		     LBL #ltop,
		     ARG0 #index,
		     ARG1 #xarg,
		     ARG2 #dtr ] >,
	     HCONS.LIST < >  ],
	  ARGS < [ SYNSEM [ NON-LOCAL #nl,
		            LOCAL [ CAT [ HEAD noun & [CASE loc],
		                          VAL.SPR < > ]],
			            CONT.HOOK [ INDEX #dtr ]]] > ].

Locative verbs

In some languages, PP predicates appear with a locative verb that is not quite semantically bleached, but means something like "be-located". In this case, it seems at least arguably incorrect to have the verb not introduce any predicate of its own. Instead, it will be an example of trans-first-arg-raising-lex-item-1:
locative-verb-lex := verb-lex & trans-first-arg-control-lex-item &
  [ SYNSEM.LOCAL [ CAT.VAL [ SUBJ < #subj >,
                             COMPS < #comps >,
                             SPR < >,
                             SPEC < > ],
                   CONT.HOOK.XARG #xarg ],
    ARG-ST < #subj &
             [ LOCAL [ CONT.HOOK.INDEX #xarg,
                       CAT [ VAL [ SPR < >,
                                   COMPS < > ],
                             HEAD noun ] ] ],
             #comps &
             [ LOCAL.CAT [ VAL [ COMPS < > ],
                           HEAD adp ] ] > ].

Note that there are many share constraints between this and copula-verb-lex. If you have both, please make a supertype for the shared constraints.

The lexical entry for the locative verb can introduce "_be+located_v_rel" as its LKEYS.KEYREL.PRED.

If you have a locative verb that takes NP complements, then it is best analyzed as a simple transitive verb with the PRED value "_be+located_v_rel".


APs, PPs and locative NPs as stand-alone predicates

If your language allows APs and PPs as stand-alone predicates, the basic strategy is to modify the selecting contexts for sentences (initial symbol, clause embedding verbs) to generalize the requirements on HEAD. This needs to be done slightly differently depending on how tense/aspect are marked in these clauses.

For locative NPs as stand-alone predicates, modify the PP over NP rule introduced above to have a non-empty SUBJ list, as noted.

Note that some languages don't have adjectives at all, just a class of stative intransitive verbs. For present purposes, the definitive test is what happens when these elements modify nouns. If they appear to enter the same construction as relative clauses headed by transitive verbs (and non-stative intransitives), then they're just verbs. However, for the purposes of the MT exercise, it will be helpful to have their PRED values end in _a_rel, rather than _v_rel.

Non-empty SUBJ values

The first step is to get from the attributive entries for As or Ps (or both) to predicative uses. It may be possible to use one and the same lexical entry in both uses. To enable predicative uses, your As or Ps (or both) need to have non-empty SUBJ lists. The sole element of the SUBJ list should be an NP or PP as appropriate (with appropriate constraints on its CASE value), and share its INDEX with the XARG and ARG1 of the A/P. (This index sharing is the same as with the MOD value.)

Finally, if some but not all As or Ps can serve as predicates, you can handle this by declaring a new feature, PRD, on the type head. Make the attributive-only As/Ps [PRD -], and any predicative-only ones [PRD +]. Then edit the root condition to require [PRD +]. This can also be useful if you have different inflection for predicative v.\ attributive uses of adjectives.

head :+ [ PRD bool ].

Unrestricted tense/aspect

If an AP or PP stand-alone predicate has underspecified tense and aspect (i.e., can be used in any tense/aspect context) or if it actually takes tense/aspect markers directly, then you can allow for AP or PP predicates by redefining the selecting contexts. In particular:

Note that even if it is possible to use a copula for, e.g., past tense AP/PP predicate sentences, you might still have unrestricted tense/aspect on the copulaless counterparts of these sentences. The key question is whether the copulaless sentences are necessarily interpreted as having a particular tense/aspect value. If so, see the next section.

Restricted to (e.g.) present tense sentences

If APs or PPs without a copula are interpreted as having some specific tense/aspect value (e.g., present tense) then these sentences need to have their TENSE value constrained. I see several ways of doing this. Though none jumps out yet as ideal (especially at a cross-linguistic level), the third one is probably the best of the bunch. If you need one or more elaborated, please post to Canvas:
  1. The selecting contexts are bifurcated allowing [HEAD verb] constituents (with any tense/aspect value) and [HEAD adp] or [HEAD adj] or [HEAD +jp] constituents with only a particular tense/aspect value. This would be reasonably easy for the root condition (you can have more than one, just define them in roots.tdl and then reference them in the definition of *start-symbol* in lkb/globals.lsp). It's a bit clunkier in the case of clause-embedding verbs, which would need two entries each.
  2. There is a non-branching rule that turns a PP/AP headed constituent into something that looks like an S ([HEAD verb, SUBJ < >, COMPS < >]), and along the way fills in the tense information.
  3. You write lexical rules to create predicative and attributive forms of As/Ps from uninflected base forms (even if there is no overt morphology involved). One rule gives [ PRD + ] forms which have the specific TENSE value required. The other makes [ PRD - ] forms. In this case, if the copula can combine with APs/PPs, it would actually take the [ PRD - ] ones, so it can fill in different tense information.

NPs as stand-alone predicates

Finally, we come to the case of (non-locative) NPs used as predicates without any supporting verb. As with NPs used as the complement of a copula, we need to do something to get an extra predication in. Here, I think the best solution is a non-branching non-headed phrase structure rule which takes an NP daughter and produces a VP mother. It should introduce the "_be_v_id_rel" relation through the C-CONT.RELS, linking the C-CONT.INDEX to the ARG0 of this relation. If NPs as stand-alone predicates necessarily get present tense interpretation, this rule can also fill in that information.

Here is a version of the rule we worked out in class for Halkomelem in 2013. Note that in Halkomelem (hur), the nouny predicates are actually N-bars. This means the rule has to fill in the quantifier rel as well as the "_be_v_id_rel".

n-bar-predicate-rule := unary-phrase & nocoord &
  [ SYNSEM [ LOCAL.CAT [ HEAD verb,
	  	         VAL [ COMPS < >,
			       SUBJ < [ LOCAL [ CONT.HOOK.INDEX #arg1,
					         CAT [ HEAD noun,
				      VAL.SPR < > ] ] ] > ] ],
             NON-LOCAL #nl ],
    C-CONT [ HOOK [ LTOP #ltop,
		    INDEX #index,
		    XARG #arg1 ],
	     RELS.LIST < arg12-ev-relation &
		   [ PRED "_be_v_id_rel",
		     LBL #ltop,
		     ARG0 #index,
		     ARG1 #arg1,
		     ARG2 #arg2 ],
		   quant-relation &
		   [ PRED "exist_q_rel",
		     ARG0 #arg2,
		     RSTR #harg ] >,
	     HCONS.LIST < qeq & [ HARG #harg, LARG #larg ] > ],
    ARGS < [ SYNSEM [ LOCAL [ CAT [ HEAD noun,
		 		    VAL.SPR cons ],
			      CONT.HOOK [ INDEX #arg2,
	                                  LTOP #larg ]]],
	              NON-LOCAL #nl ] > ].

If you also need a non-branching rule for tense-restricted PP or AP predicates, you might consider doing those the same way (VP over PP/AP), and sharing many constraints between the two rules. Note, however, that the PP/AP rule would have an empty C-CONT.RELS list.


Check your MRSs

Here are some sample MRSs to give you a sense of what we're looking for. Note that yours might differ in detail, because of e.g., different tense values or the use of a locative verb.

The cat is hungry.

The cat is in the park.

The cat is the dog.

Back to top

Test wh questions in non-verbal predicates

Many of you, when looking for examples of wh questions, turned up examples like Who/what is that? or Where is Kim?. In this part of the lab, the question I'd like you to answer is: do the analyses of wh questions and non-verbal predicates you have implemented so far work together appropriate to analyze these sentences?

If you already have the exmaples, try parsing them and document what happens.

If you don't, but can find them quickly, please do so and then document what happens when you try to parse them. If they are not easily accessible, it is fine to skip this part of the lab.

Run both the test corpus and the testsuite

Following the same procedure as usual, do test runs over both the testsuite and the test corpus.

Collect the following information to provide in your write up:

  1. How many items parsed?
  2. What is the average number of parses per parsed item?
  3. How many parses did the most ambiguous item receive?
  4. What NEW sources of ambiguity can you identify?

Back to top

Write up

Your write up should be a plain text file (not .doc, .rtf or .pdf) which includes the following:

  1. A description of how non-verbal predicates work in your language, including IGT.
  2. A description of your implementation of these phenomena, including:
  3. A description of how items 15-17 are currently working in the MT set up for you. Do they go through? How much ambiguity? If they don't go through, how do the MRSes differ?
  4. A description of how wh questions of non-verbal predicates work in your language (if available) and what happened when you tried parsing them (after adding non-verbal predicates).
  5. A description of the performance of your final grammar for this week on the test suite and test corpus, as compared to your starting grammar (see details above).

Back to top

Submit your assignment

Back to top

Back to course page


Last modified: