Agrammatism refers to a language disturbance; difficulty in the production and comprehension of grammatical features, such as proper use of function words, word endings, and word order.
Often seen in cases of Broca's aphasia.
Other /More definition:
Agrammatism refers to speech in which there is a lack of grammatical structure, such as the absence of grammatical morphemes and function words
Lexicon of Psychology - Terms, Treatments, Biographies,