Notes on computational linguistics.pdf - UCLA Department of ...

Stabler - Lx 185/209 2003
ɛ:: =T C ɛ:: =T +wh C
ɛ:: =v +k T ɛ:: =V =D v
eat:: =D +k V laugh:: V
the:: =N D-k which::=N D -k -wh
king:: N pie:: N
With this grammar, we can derive strings of category C as follows, where in these trees the leaves are lexical
items, a node with two daughters represents the result of merge, and a node with one daughter represents the
result of a move.
thekingthepieeat:C
ɛ:: =T C thekingthepieeat:T
the pie eat: +k T, the king: -k
ɛ:: =v +k T the pie eat: v, the king: -k
the pie eat: =D v
ɛ:: =V =D v the pie eat: V
eat: +k V, the pie: -k
eat:: =D +k V the pie: D -k
the:: =N D -k pie:: N
the king: D -k
the:: =N D -k king:: N
which pie the king eat: C
the king eat: +wh C, which pie: -wh
ɛ:: =T +wh C the king eat: T, which pie: -wh
eat: +k T, the king: -k, which pie: -wh
ɛ:: =v +k T eat: v, the king: -k, which pie: -wh
eat: =D v, which pie: -wh
ɛ:: =V =D v eat: V, which pie: -wh
eat: +k V, which pie: -k -wh
eat:: =D +k V which pie: D -k -wh
which:: =N D -k -wh pie:: N
the king: D -k
the:: =N D -k king:: N
Since merge is binary and move is unary, it is easy to see that the tree on the left has two movements, while
the one on the right has three.
Let’s elaborate this example just slightly, to introduce auxiliary verbs. We can capture many of the facts
about English auxiliary verb cooccurrence relations with the mechanism of selection we have defined here.
Consider for example the following sentences:
He might have been eating He has been eating He is eating
He eats He has been eating He has eaten
He might eat He might be eating He might have eaten
If we put the modal verbs in any other orders, the results are no good:
* He have might been eating * He might been eating * He is have ate * He has will eat
The regularities can be stated informally as follows: 44
(3) English auxiliaries occur in the order MODAL HAVE BE. So there can be as many as 3, or as few as 0.
(4) A MODAL (when used as an auxiliary) is followed by a tenseless verb, [-tns]
(5) HAVE (when used as an auxiliary) is followed by a past participle, [pastpart]
(6) Be (when used as an auxiliary) is followed by a present participle, [prespart]
(7) The first verb after the subject is always the one showing agreement with the subject and a tense marking
(if any), [+tns]
44 Many of these auxiliary verbs have other uses too, which will require other entries in the lexicon.
(1) He willed me his fortune. His mother contested the will. (WILL as main verb, or noun)
(2) They can this beer in Canada. The can ends up in California. (CAN as main verb, or noun)
(3) The might of a grizzly bear is nothing to sneeze at. (MIGHT as noun)
(4) I have hiking boots. (HAVE as main verb)
(5) I am a hiker. (BE as main verb)
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