Practical Work 3
Grammar Development

Templates with Arguments

Download grammar2.lfg and take a good look at it. Expand it so that the following sentences are assigned a sound analysis:

• the girl gave the dog a bone
• the girl gives the gorilla bananas
• gorillas devour bananas
• a gorilla devours bananas

The verb give ist a three-place verb. Assume the following subcateogrization frame: SUBJ, OBJ, OBJ2. Assume that the object is always to the right of the verb in English.

Your grammar should contain the following:

• A template for transitive verbs
• A template for intransitive verbs
• A template for ditransitive verbs
• A template OPT-TRANS that calls up templates for transitive and intransitive verbs (for verbs like eat, which can be used transitively or intransitively).
• Templates for for number and person so that this information can be called up via templates in the noun entries.
• All your verbal lexical entries should call up their subcategorization information, their subject-verb agreement information and their tense-aspect-moood information via templates.

Feature Unification

These sentences should not work:

• the girl give the gorilla bananas
• gorillas devours bananas
• gorilla devour bananas
• gorillas devours banana

Remember that there are several ways to formulate constraints on f-structures.

• = assigns a value to an attribute (e.g., (^ DEF) = +)).
• ~= says that an attribute should not have this value (e.g., (^ DEF) ~= +)).
• =c says an attribute is constrained to have a certain value, but that this value should be provided in another part of clause (e.g., (^ DEF) =c +)). This is called a constraining equation.
• Just providing the attribute and no value is a so-called existential contraint, e.g., (^ DEF). This means that this attribute is considered to exist and that a value must be provided by another part of the clause.

Testsuites

Create a testsuite of sample sentences and keep testing your progress with respect to the testsuite (see XLE Documentation for many details). Remember to do regression testing to make sure your grammar does not lose capabilities you had already implemented.

Lexical Rules, First look at PPs

The file grammar2.lfg also already contains a lexical rule for the passive. It also contains a simplified treatment of PPs. Use these as a basis for building a lexical rule for the English Dative Shift. See the part on templates and lexical rules in the XLE documentation for more information.

This lexical rule should interact with the lexical rule for the passive so that one can also parse passives of ditransitive verbs.

Update your templates for transitive and ditransitive verbs using the two lexical rules (in interaction, if applicable).

Expand your grammar so that the following sentences also work:

• the girl gives a bone to the dog
• the zookeeper gave a banana to the gorilla
• the dog was given a bone by the girl
• a bone was given to the dog by the girl

These sentences should not work:

• the girl gave to the dog a bone
• the dog was given by the girl a bone

That is, you need to make sure that the NPs and PPs appear in the right order.

Be sure to add all of the sentences to your (growing) testsuite. Mark the ones that should not work with a 0!. See the part on Test Files and Tree Banks in the XLE user documentation for more information.

Your grammar should contain (at least) the following:

• Lexical rules for passive and Dative Shift in the TEMPLATE section.
• C-structure rules in the RULES section which allow for OBLs PPs.
• The LEXICON section has to be expanded to take care of any new lexical items.