Analyzing Features of Grammatical Categories

Show my head to the people; it is worth seeing.

--Feature structure, to Ivan Sag in a dream

CFG’s: Chock Full of Goofs

Requires massively redundant rules Fails to capture generalizations

S→NP-3p-sg VP-3p-sg S→NP-3p-pl VP-3p-pl S→NP1 VP1 S→NP2 VP2

Rules are arbitrary S→NP1 VP2

HPSG: How to Phix Subpar cfGs Change atomic categories into categories

that can be decomposed into features.

Let’s get our terms straight

universityNAME Stanford Univ.FOUNDERSPRESIDENTTEL

feature structure

typefeature value

More complex structures

Embedding, see p. 54, fig.7a Indexes

Department

TEL [1] 650-723-4284

CHAIR [TEL [1] ]

HPSG Types and Features

Initial type hierarchy, p. 61, fig. 25

HPSG Types and Features

Initial type hierarchy, p. 61, fig. 25 First important subtypes divide expressions

into words and phrases

HPSG Types and Features

Initial type hierarchy, p. 61, fig. 25 First important subtypes divide expressions

into words and phrases All expressions have the feature HEAD

HPSG Types and Features

Initial type hierarchy, p. 61, fig. 25 First important subtypes divide expressions

into words and phrases All expressions have the feature HEAD with a

value from the pos types

HPSG Types and Features

Initial type hierarchy, p. 61, fig. 25 First important subtypes divide expressions

into words and phrases All expressions have the feature HEAD with a

value from the pos types

Agreement

Some pos types exhibit agreement, so we group them into their own subtype agr-pos, which carries the feature AGR

AGR feature takes the value agr-cat, which is a sub-type of feature-structure

It has (at least) the features PER and NUM PER takes the values {1st,2nd,3rd} NUM takes the values {sg, pl} See p. 70, fig. 49

How much of this is universal?

Other languages have different values?

All languages have all features and values, but optimality-like constraints ensure that only some show up?

The VAL feature

A feature of expressions

The VAL feature

A feature of expressions Takes the value val-cat, which has the

features COMPS and SPR

The VAL feature

A feature of expressions Takes the value val-cat, which has the

features COMPS and SPR These “represent the combinatoric potential

of the word or phrase”

The VAL feature

A feature of expressions Takes the value val-cat, which has the

features COMPS and SPR These “represent the combinatoric potential

of the word or phrase” COMPS takes the value itr, str, or dtr; p.62,

fig. 27 All expressions have this feature (so far)

Underspecification

A type can be unspecified for a particular feature

This picks out a larger class of feature structures (it includes more kinds of feature structures)

Underspecification allows some kinds of generalizations that we couldn’t get from CFGs, p. 63, fig.28

The SPR feature

A generalization of the notion ‘determiner’ Distinguishes N, NOM, and NP SPR + for NP SPR – for NOM

The SPR feature

A generalization of the notion ‘determiner’ Distinguishes N, NOM, and NP SPR + for NP SPR – for NOM SPR + or SPR – for N

The SPR feature

A generalization of the notion ‘determiner’ Distinguishes N, NOM, and NP SPR + for NP SPR – for NOM SPR + or SPR – for N

Also used to distinguish S and VP S is SPR + VP needs a subject NP to the left, so it is SPR – Huh? p. 64, fig. 34

Diagramming for Dollars

Diagramming for Dollars

Team 1: lexical entry for the noun “verb”

As in, “Weird can be a verb”

Team 2: lexical entry for the verb “verbs”

As in, “Calvin verbs the word ‘weird’.”

Diagramming for Dollars

Round 1: lexical entries Round 2: p. 65, fig. 37a

Diagramming for Dollars

Round 1: lexical entries Round 2: p. 65, fig. 37a Round 3: p. 69, fig. 47

Agreement Rule

Agreement features get “passed up” from daughters to mothers

See rule, p. 70, fig. 50 Tree in 51

Head Feature PrincipleThere is a wisdom of the head…

--Charles Dickens

Every headed phrase has a head daughter with the same head values

General form: p. 72, fig. 53 Headed rules: p. 73, fig. 54, esp. 54d

Diagramming for Dollars

Round 1: lexical entries Round 2: p. 65, fig. 37a Round 3: p. 69, fig. 47 Round 4:

“LING7420 loves HPSG.”

“The professor cheers.”