Agrammatism, syntactic theory, and the lexicon: Broca's area and the development of linguistic ability in the human brain

Grodzinsky's Tree-Pruning Hypothesis can be extended to explain agrammatic comprehension disorders. Although agrammatism is evidence for syntactic mod ularity, there is no evidence for its anatomical modularity or for its loca lization in the frontal lobe. Agrammatism results from diffuse left hemisph ere damage - allowing the emergence of the limited right hemisphere linguis tic competence - rather than from damage to an anatomic module in the left hemisphere.