Assignment 9: Construction Grammar Learning
Assigned Thursday, April 24th
Due Thursday, May 1st, by 11:59pm - submit electronically.

This assignment involves two parts. The first is to get you familiar with the sentence analysis process, and the second to understand the grammar learning algorithm. You will be using a construction grammar analyzer to analyze sentences using a simple grammar written in ECG (Embodied Construction Grammar). You will then be asked to predict the result of grammar learning by examining sets of input tokens.

Please read O8, O9, Book Ch 25, and the Construction Grammar/ECG lecture slides before beginning this assignment.

Analyze some sentences

RETURNED ANALYSIS
____________________________
Cost: -37.281867111870255
Analysis: ROOT(0, 5)

	Constructions Used:

		ROOT[0] (0, 5)
		Transitive-Cn[2] (0, 5)
		I-Cn[5] (0, 1)
		...

	Schemas Used:

		Move[17]
		Place[18]
		...

	Semantic Constraints:
	
		CauseMove[3].direction <-->
		Move[17].direction
			Filler: Place[18]
		...
		
...
Surviving parser states incorporating up through the word "I"

-------------------------------------------------------------------------------------------

Finally, try typing in the sentence bring the cup (no capitalization or punctuation!). Notice that the analyzer fails to find a construction which spans the sentence; only single-word constructions appear in the analysis (struck out on May 2, 10 am in response to Nathan's post to the newsgroup). Check this against the grammar: the transitive construction requires three constituents—the agent, the verb, and the object. We know of course that the sentence is grammatically well-formed, but this grammar has not yet learned the imperative-mood form of bring.

Part I: Analysis

Using a9.prefs, analyze the following sentences:

(a) I will bring you the cup

What is the difference between this analysis and the one for I will bring the cup? How is this difference captured in the grammar?

(b) I will bring the cup here

Does the analyzer find a spanning analysis? Why or why not? How does the analysis account for the destination of the bring action, if at all?

(c) * Nomi give I the ball

Does the analyzer find a spanning analysis here? If it does not, explain why. If it does, propose a change to the grammar that will exclude this sentence from being admitted as grammatical.

Part II: Learning

Now load in nomi.prefs. This grammar is nearly identical to the first one except it does not contain the following two constructions: the transitive construction and the ditransitive construction. (It also has most constructions descending from RootType; this is so the analyzer can treat words individually, rather than expecting a construction that will span multiple words.) It contains a number of basic schemas and mostly lexical constructions (and a phrase red ball). This approximates the single-word stage in child language acquisition.

Assume that this is the initial grammar that the child learner (Nomi) is using at the beginning of a play time one day. Remember that when a child acquires language, she has a lot of background knowledge as well as contextual knowledge at her disposal. Below is a pictorial description of the scene in which the utterances were said. In the learning system code, this scene will be encoded as a number of schemas linked together. The scene includes the following descriptive knowledge:

• Nomi (and her parents, not shown) are playing in the living room;
• the doll (which Nomi refers to as the baby), the teddy bear, and the red ball are lying around on the floor in the living room;
• the books are in a box on the floor;
• the jug of orange juice, the oranges, and the cup are on the dining table in the kitchen.

Over the course of interacting with her parents and playing with toys, Nomi hears the following six utterances from her parents, accompanied by some context:

1. (Father) I will bring you some juice - Father went and retrieved the jug of orange juice from the dinning table.
2. (Father) I will get a cup for you Nomi - Father brought over the cup for Nomi.
3. (Mother) Nomi you can get a book and bring it back here - Mother also gestured at the books and then made a familiar "come here" gesture.
4. (Mother) now get the red ball Nomi - Mother shifts her attention to the red ball that is sitting among Nomi's toys.
5. (Father) would you get that and give it to me please - Father reiterated Mother's request for the red ball while pointing to the red ball.
6. (Mother) get the baby and bring her to bed - Mother got up and waved for Nomi to come along to the bedroom.

Assume that Nomi is a linguistically precocious child, so that she hypothesizes new constructions (albeit lexically specific ones) with every utterance she hears. According to the verb-island hypothesis, children tend first to learn verb-specific constructions (e.g. get-ball construction, or throw-block construction) and then later on to generalize across verbs. Based on this principle, as well as the three learning mechanism we discussed in lecture (relational mapping, merging, composing), simulate by hand what Nomi might learn from these sentences.

1. For each utterance listed above:
   1. Analyze the sentence using nomi.prefs, and compare the SemSpec against what is available in the context.
   2. State any relational mapping operations that may be performed and write down the new construction (if any) in ECG notation (i.e., as it appears in the analyzer). Focus on verb island constructions combining 2 or 3 words. (There is no need to try to make these work in the analyzer.)
   3. To help make this clearer, here is one construction that might be learned from sentence 1. Note that it is essentially a mapping of the CauseMove that Nomi observed onto the sentence she heard (which she partially understood).
      

      construction Bring-Juice-Cn
      
        constructional constituents
          bring: Bring-Cn
          juice: Juice-Cn
      	
        form constraints
          bring.f before juice.f
      	
        meaning
          evokes Father as father
          evokes Nomi as nomi
          constraints
            bring.m.agent <--> father
            bring.m.direction <--> nomi
            bring.m.patient <--> juice.m
      

2. At the end of the six utterances, state two learning-by-merging operations that can be performed on the new sets of constructions Nomi just acquired.
   

Notes

transitive: A transitive verb takes a subject and a (direct) object; an intransitive verb takes no object; and a ditransitive verb takes a subject and two objects (one direct, the other indirect).

Readings

O8, O9, Book Ch 25