Geoffrey Keith Pullum (/ˈpʊləm/; born 8 March 1945) is a British and American linguist specialising in the study of English.

He was co-founder of Language Log and a contributor to Lingua Franca at The Chronicle of Higher Education, often criticizing prescriptive rules and linguistic myths.

Geoffrey K. Pullum was born in Irvine, North Ayrshire, Scotland, on 8 March 1945, and moved to West Wickham, England, while very young.

He left secondary school at age 16 and toured Germany as a pianist in the rock and roll band Sonny Stewart and the Dynamos.

[6] After the band broke up, Pullum enrolled in the University of York in 1968, graduating in 1972 with a Bachelor of Arts with first class honours.

[7] Pullum's work in the 1970s with Desmond Derbyshire, for whom he was the primary doctoral supervisor, established the existence of object-initial languages.

[17] In 2004, Barbara Scholz, Pullum, and James Rogers initiated a group project on the applications of model theory in syntax, which was supported by the Radcliffe Institute for Advanced Study at Harvard University in 2005–2006.

We can say in very broad terms that a human language is a characteristic way of structuring expressions shared by a speech community; but that is extremely vague, and has to remain so.

In other words, model-theoretic grammars aim to describe the possible structures in a language, rather than focusing on the process of generating sentences.

X-bar theory is a specific type of phrase-structure grammar that posits a uniform structure for all phrasal categories, with each phrase containing a "head" and optional specifier and/or complement.

Pullum argues that the traditional notion of a noun phrase is correct, and that the so-called DP hypothesis is mistaken.