Linguistics 567: Knowledge Engineering for NLP

Lab 8 Due 5/19


Some of you may have already covered some of this material. If you would like to work on something else this week, let me know what it is.

Run a base-line test suite instance, and save this to submit with your lab. As usual, consider adding to your basic test suite if you have not sufficiently covered the phenomena addressed here.

Part 1: Optional arguments


The goal of this lab is to allow for unexpressed arguments. As many of you have noticed, there are plenty of languages that don't use pronouns as much as English does, but rather leave the NP out entirely if it was just going to be a pronoun. Generally, the meaning is about as recoverable from context as it is with pronouns (afterall, pronouns only give small clues to the referent in terms of person, number, and gender; among 3rd person referents, that usually leaves a lot of ambiguity). In some languages (e.g., Spanish), this kind of pronoun omission seems to be 'licensed' by the fact that the verbal inflections carry as much information as the pronouns would. In other languages (e.g., Japanese), the verbal inflections don't in fact carry person/number/gender information, but pronouns still aren't required.

Even in English (which likes pronouns so much that it has two expletive [meaningless] ones -- it and there) there are cases where arguments appear to be optional. Prime examples are verbs like eat and drink. The sentence I already ate means 'I already ate something', but the addressee is in no way expected to know what exactly was eaten. This is called indefinite null instantiation (see e.g., Johnson and Fillmore 2000) This contrasts with definite null instantiation (ibid), in which null arguments have definite reference, that is, the utterance is only felicitous if the addressee can determine the referent. English verbs which do this include tell as in I already told you. (Which is a cute example, because it's most likely to be used in a case where the addressee can't determine what exactly s/he was already told, but it's licensed because it means something like 'I already told you the answer to that question'.)

Our general strategy is going to be similar to the way we handled missing determiners. That is, we're going to write unary phrase structure rules in which the mother and single daughter have different valence requirements.

I believe that most languages should fall into one of the following patterns (restricting our attention to verbs and their arguments):

I've written this assignment based on those four possibilities, and it should be straight-forward to the extent that I'm right :-). If your language instantiates a different pattern, talk to me.

Create instances of rules

Add ditransitive verbs

If you don't already have any verbs that take three arguments, try putting one in:

Add verbal subtypes for argument optionality

For expository purposes, I'm assuming that you have subtypes of verb-lex called trans-verb-lex and ditrans-verb-lex. If you've called them something else, not to worry, just use your corresponding types whenever I mention these.

For languages without general pro-drop of objects

For languages with general pro-drop of objects

For languages where arugment optionality corresponds to the presence of optional verbal inflection

Part 2: Modification

In this part, you will add basic functionality for intersective adjectives and adverbs.

Head-modifier rules

The Matrix distinguishes scopal from intersective modification. We're going to pretend that everything is intersective and just not worry about the scopal guys for now.



Write up

Submit via ESubmit

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