Less is more in language production: Shorter sentences contain more informative words

Abstract

AbstractAgrammatism is characterized by short sentences, the omission of function words, a higher ratio of heavy to light verbs, and a decreased use of verbs relative to nouns. Despite the observation of these phenomena more than two centuries ago, there has been no unifying theory to explain all features of agrammatism. Here, by first examining the language of patients with primary progressive aphasia, we show that the seemingly heterogeneous features of agrammatism can be explained by a process that selects lower frequency words over their higher frequency alternatives in the context of a limitation in sentence production, likely to increase the informational content of sentences. We further show that when healthy speakers are constrained to produce short sentences, features of agrammatism emerge in their language. Finally, we show that these findings instantiate a general property in healthy language production in which shorter sentences are constructed by selecting lower frequency words.