Unification grammar

Trying to solve the same problems

Transformational Grammar has PSRs

Transformational Grammars ALSO
need MOVEMENT

Structure-sharing MEANS unification

And VERY complicated information IN
words!

Head-driven Phrase Structure
Grammar

HPSG is the most popular Unification
Grammar

PHON is phonological or sound-related
information

Unless they’re PHONologists!

SYNSEM is the syntactic and semantic
information

CAT carries the syntactic features

CONTENT and CONTEXT is the
semantic info

[She] CONTENT
• PER 3rd
• NUM sing
• GEND fem

HEAD attribute is verb
[walks][walks]

[walks] has VALENCE attributes
[walks][walks]

VALENCE is also known as SUBCAT
[walks][walks]

VALENCE/SUBCAT who cares?
[walks][walks]

VALENCE sounds more scientific
[walks][walks]

VALENCE means attract or repel
[walks][walks]

[walks] attracts a noun
[walks][walks]

[walks] attracts a subject
[walks][walks]

[walks] specifies information about the
subject
[walks][walks]

[walks]
SUBJ<CAT|HEAD noun|CASE nominative
CONT [1]|PER 3rd
NUM sing
GEND –
CONT|walker
[1]

CONT of subject matches in CONT of
the verb
CONT [1]|PER 3rd
NUM sing
GEND –
CONT|walker
[1]

If the verb takes [she] as a subject …
CONT [1]|PER 3rd
NUM sing
GEND –
CONT|walker
[1]

CONT [1] matches CONT of [she]
CONT [1]|PER 3rd
NUM sing
GEND –
CONT|walker
[1]

If the verb takes [she] as a subject
CONT [1]|PER 3rd
NUM sing
GEND –
CONT|walker
[1]

So when [walks] takes [she] …
CONT [1]|PER 3rd
NUM sing
GEND –
CONT|walker
[1]

This …
CONT [1]|PER 3rd
NUM sing
GEND –
CONT|walker
[1]

… becomes this
CONT [1]|PER 3rd
NUM sing
GEND fem
CONT|walker
[1]

[walks] VALENCE features and CONT
features

Usually marked with a number in a
square

Why is it a number in a square?

Or a funny shape – it doesn’t matter

The number in the square shows the
structure-sharing

That’s it!
STRUCTURE A = [m _ t _ h]
STRUCTURE B = [_ a _ c _]
Unify A and B
What happens?
A+B = [match]
That’s it!

It looks complicated
STRUCTURE A = [s _ a _ e]
STRUCTURE B = [_ h _ r _]
Unify A and B
What happens?
A+B = [share]
But it’s basically very simple (and no movement)

Here’s some [walks] info again!

Notice the VALENCE specifications

[Walks] attracts a NP with nominative
case

Walks attracts a NP with CONT
[3rd,sing]

No problem
• She walks
• That’s a good sentence
• What about this?
• Her walks
• Is that a good sentence?
• No
• Why?

[her] is CASE acc (accusative)

But it is the wrong syntactic CATEGORY

So don’t panic …
[walks][walks]

… when you see these complicated
AVMs
[walks][walks]

It takes a bit of time …
[walks][walks]

You have to get used to it
[walks][walks]

But it’s basically very simple
[walks][walks]

And no movement
[walks][walks]

Don’T forget -- VALENCE features
[walks][walks]

VALENCE or SUBCAT
[walks][walks]

Unification grammar

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Unification grammar