LING 505 NOTES 4/15
- yield of a tree: string of terminal symbols
o example: a sentence
 we can’t say “I have.”
 need an object to complete the transitive verb
phrase
- consider a grammar G
G = < {a,b}, {S, A, B}, S, R >
{a,b} are terminal symbols
{S, A, B} are nonterminals
S is a start symbol
R is a set of rules
R = {S  AB, A  aAb, A  e, B Bb, Bb}
With this set of rules, the right side of the tree will have only ‘a’s
and ‘b’s, while the left side has both ‘a’s and ‘b’s.
S  AB is obligatory because it begins the tree.
A  e and B b are obligatory because they are the only way to end the
tree ( they don’t involve nonterminals).
- Context-sensitive rules:
o Example from English morphology/phonology
 liked >> /t/  class 1 verb
 loved >> /d/  class 2 verb
 kidded >> /əd/  class 3 verb
o Why the difference?
 the nonterminal past tense form, here represented as [-ed
past], is pronounced differently depending on context.
 class 1 verbs, in which [-ed past] is expressed as /t/, end
in voiceless sounds
 class 2 verbs, in which [-ed past] is expressed as /d/, end
in voiced sounds
 class 3 verbs, in which [-ed past] is expressed as /əd/
end in either /t/ or /d/
o This rule is context sensitive because the [-ed past] takes a
different form depending on the surrounding context of the
word
- Look at example 16-6 in book
o the idea of node admissibility vs. tree generation is
important to how we understand comprehension vs.
production in language
o During comprehension, we (supposedly) judge
grammaticality based on whether a sentence meets the
required conditions, not on how the sentence was
generated
- Chomsky hierarchy
o type 1 – context-sensitive
o type 2 – context free
o type 3 – regular, right linear
- Kornai and Pullum article
o Consider “the new Spanish math teacher”
o there is hierarchy to the phrase
o we assume “teacher” as head of the phrase
o use the “one-substitution” test to test relative attachedness
of nouns
 we can say “the new Spanish math teacher is better
than the old one” but not “the new Spanish math
teacher is better than the old physics one.”
 ‘math’ is attached to teacher before ‘Spanish’ is
o X-Bar
 assume an x-phrase (XP), a y-phrase (YP) a
component x’ (x-bar)
 XP  YP x’
 x’  x zP
 x’  x’ wP
o one syntactic approach:
 propositional content of a phrase is contained in verb
phrase
o X-Bar is important in establishing that all types of phrases
have essentially the same structure
o Principles:
 Lexicality: all nonterminals correspond to a terminal
 all phrasal categories come from lexical
categories, so a Noun Phrase must contain a
Noun, etc.
 Optionality: only the heads in a phrase are necessary
 So, in the phrase “the new Spanish math
teacher,” only “teacher” is necessary and all
other nouns are auxiliary