What is Syntax?
ANLP: Week 5, Unit 1
Shay Cohen
Based on slides from ANLP 2019
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Computing meaning
A well-studied, difficult, and un- solved problem.
Fortunately, we know enough to have made partial progress (Wat- son won).
Over the next few weeks, we will work up to the study of systems that can assign logical forms that mathematically state the meaning of a sentence, so that they can be processed by machines.
Our first stop will be natural language syntax.
Natural language syntax
Syntax provides the scaffolding for semantic composition.
The brown dog on the mat saw the striped cat through the window.
The brown cat saw the striped dog through the window on the mat.
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Natural language syntax
Syntax provides the scaffolding for semantic composition.
The brown dog on the mat saw the striped cat through the window.
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Natural language syntax
Syntax provides the scaffolding for semantic composition.
The brown dog on the mat saw the striped cat through the window.
The brown cat saw the striped dog through the window on the mat.
Do the two sentences above mean the same thing? What is the process by which you computed their meanings?
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Constituents
Words in a sentence often form groupings that can combine with other units to produce meaning. These groupings, called consituents can often be identified by substitution tests (much like parts of speech!)
Kim [read a book], [gave it to Sandy], and [left] You said I should read the book and [read it] I did. Kim read [a very interesting book about grammar].
Constituents have structure
English NPs are commonly of the form:
(Det) Adj* Noun (PP | RelClause)*
NP: the angry duck that tried to bite me,
VPs are commonly of the form:
(Aux) Adv* Verb Arg* Adjunct*
Arg → NP | PP
Adjunct → PP | AdvP | …
VP: usually eats artichokes for dinner, .
In Japanese, Korean, Hindi, Urdu, and other head-final languages, the head is at the end of its associated phrase.
In Irish, Welsh, Scots Gaelic and other head-initial languages, the head is at the beginning of its associated phrase.
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Heads and Phrases
Noun (N): Noun Phrase (NP)
Adjective (A): Adjective Phrase (AP)
Verb (V): Verb Phrase (VP)
Preposition (P): Prepositional Phrase (PP)
So far we have looked at terminals (words or POS tags).
Today, we’ll look at non-terminals, which correspond to
phrases.
The part of speech that a word belongs to is closely linked to
the type of constituent that it is associated with.
In a X-phrase (eg NP), the key occurrence of X (eg N) is called the head, and controls how the phrase interacts (both syntactically and semantically) with the rest of the sentence.
In English, the head tends to appear in the middle of a phrase.
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Constituents have structure
English NPs are commonly of the form:
(Det) Adj* Noun (PP | RelClause)*
NP: the angry duck that tried to bite me, head: duck.
VPs are commonly of the form:
(Aux) Adv* Verb Arg* Adjunct*
Arg → NP | PP
Adjunct → PP | AdvP | …
VP: usually eats artichokes for dinner, .
In Japanese, Korean, Hindi, Urdu, and other head-final languages, the head is at the end of its associated phrase.
In Irish, Welsh, Scots Gaelic and other head-initial languages, the head is at the beginning of its associated phrase.
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Constituents have structure
English NPs are commonly of the form:
(Det) Adj* Noun (PP | RelClause)*
NP: the angry duck that tried to bite me, head: duck.
VPs are commonly of the form:
(Aux) Adv* Verb Arg* Adjunct*
Arg → NP | PP
Adjunct → PP | AdvP | …
VP: usually eats artichokes for dinner, head: eat.
In Japanese, Korean, Hindi, Urdu, and other head-final languages, the head is at the end of its associated phrase.
In Irish, Welsh, Scots Gaelic and other head-initial languages, the head is at the beginning of its associated phrase.
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WALS – Subject Verb Object order
Taken from https://wals.info/feature/81A#2/5.6/172.8
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