A Dictionary of Linguistics and Phonetics David Crystal

368 phylogeny
generative device. Phrase-structure grammars contain rules (PS-rules) which
are capable not only of generating strings of linguistic elements, but also of
providing a constituent analysis of the strings, and hence more information
than finite-state grammars. They are not, however, as powerful as transformational
grammars, as the latter are more capable of displaying certain
types of intuitive relationship between sentences, and may ultimately be
demonstrable as simpler. In a related sense, the phrase-structure component of
a transformational grammar specifies the hierarchical structure of a sentence,
the linear sequence of its constituents, and indirectly (through the notion of
dominance) some types of syntactic relations.
The main difference between the phrase-structure grammars (PSGs) of Chomsky
as opposed to the immediate-constituent analysis of earlier linguists is that
Chomsky’s model is formalized as a system of generative rules, and aims to
avoid the emphasis on discovery procedures characteristic of the earlier
approach. In their original formulation, PSGs took the form of a set of rewrite
rules (with the abbreviations expanded here), such as:
Sentence ⇒ Noun Phrase + Verb Phrase
Verb phrase ⇒ Verb + Noun Phrase
Noun Phrase ⇒ Determiner + Noun
Various distinctions have been made in the classification of phrase-structure
grammars, of which the main division is into context-free and context-sensitive
types: a grammar consisting wholly of context-free rules (rules which are of the
form ‘Rewrite X as Y’, i.e. regardless of context) is much less powerful than a
grammar containing context-sensitive rules (rules which are of the form ‘Rewrite
X as Y in the context of Z’). In later linguistic theory several approaches to
syntax were developed which are equivalent to PSGs, but do not employ PS
rules, and are thus able to capture generalizations missed by ordinary PSGs.
Examples include generalized phrase-structure grammar and head-driven
phrase-structure grammar. The minimalist programme introduces a major
simplification of the notion (bare phrase structure). See Chomskyan.
phylogeny (n.) The application of this general term in linguistics refers to the
historical (or diachronic) development and decay of language in speech
communities, or as represented in historical texts; also referred to as phylogenesis.
Phylogenetic study contrasts with ontogeny, for the study of development in
the individual, as carried on in language acquisition.
phylum (n.)
see family
physiological phonetics
see articulatory phonetics
Piagetian see Geneva School (2)
pictogram (n.) In the study of writing systems, a term used for a symbol found
in picture writing; also called a pictograph. Pictography is the study of pictorial
systems, or an instance of such a system. The pictograms provide a recognizable
representation of entities as they exist in the world (e.g. wavy lines representing