Syntactic delay and pragmatic deviance in the language of fragile X males.

The expressive language of 19 fragile X [fra(X)] males with chronological ages between 5 and 36 years and Vineland Adaptive Behavior Scores between 21 and 79 was examined for syntactic as well as pragmatic proficiency. The production of deviant repetitive language was observed with this group, corroborating the results of an earlier study with a smaller sample of fra(X) males. In contrast, when 2 syntax scores, mean length of utterance (MLU), and Index of Productive Syntax (IPSyn) were derived from naturalistic language observations, the relation of complexity to length was observed to be very similar to the known relationship of these 2 facets of syntactic ability in normal preschoolers. These results, and the absence of correlations between syntactic scores and proportions of deviant repetitive language are consistent with the notion that the syntactic development of fra(X) males is typically delayed rather than deviant. For effective assessment and remediation of communicative problems associated with the syndrome to be developed, it is argued, language must be considered as a combination of competencies rather than as a unitary skill.