etc. There is disagreement in certain areas, for instance concerning the status of prepositions. The distinction between lexical and functional categories plays a big role in Chomskyan grammars (Transformational Grammar, Government and Binding Theory, Minimalist Program), where the role of the functional categories is large. Many phrasal categories are assumed that do not correspond directly to a specific part of speech, e.g. inflection phrase (IP), tense phrase (TP), agreement phrase (AgrP), focus phrase (FP), etc. (see also Phrase → Functional categories). In order to acknowledge such functional categories, one has to assume that the constellation is a primitive of the theory and that it exists separately from the words that appear. As a consequence, many grammar frameworks do not acknowledge such functional categories, e.g. Head Driven Phrase Structure Grammar, Dependency Grammar, etc. Note: The abbreviations for these categories vary across systems; see . Labels in the Minimalist Program Early research suggested shifting away from the use of labelling, as they were considered to be non-optimal for the analysis of syntactic structure, and should therefore be eliminated. Collins (2002) argued that, although labels such as Noun, Pronoun, Adjective and the like were unavoidable and undoubtedly useful for categorizing syntactic items, providing labels for the projections of those items, was not useful and was, in fact, detrimental to structural analysis, since there were disagreements and discussions about how exactly to label these projections. The labeling of projections such as Noun Phrases (NP), Verb Phrases (VP), and others have since been a topic of discussion amongst syntacticians, who have since then been working on labelling algorithms to solve the very problem brought up by Collins. In line with both Phrase Structure Rules and X-bar theory, syntactic labelling plays an important role within Chomsky's Minimalist Program (MP). Chomsky first developed the MP by means of creating a theoretical framework for generative grammar that can be applied universally among all languages. In contrast to Phrase Structure Rules and X-bar theory, many of the research and proposed theories done on labels are fairly recent and still ongoing. See also Dependency grammar Empty category Grammatical category Lexical category (part of speech) Merge (linguistics) Phrase Phrase structure grammar Syntax Notes References Bach, E. 1974. Syntactic theory. New York: Holt, Rinehart and Winston, Inc. Brinton, L. 2000. The structure of modern English. Amsterdam: John Benjamins Publishing Company. Brown, K. and J. Miller. 1991. Syntax: A linguistic introduction to sentence