Lexical features in speech of mentally retarded adults

The aim of this study was to investigate the lexical features including lexical richness, the total number of words, and the percentage of kinds of content words in the speech of adults with mental retardation and so to determine the percentage and to compare them with the speech of normal people. In this analytical descriptive study, investigated population was 10 mentally retarded adult with IQ 40-52 who in top educable group that their mental ages were determined through Goodenough test and were matched with 10 normal children in terms of mental age. Lexical features of descriptive and spontaneous speech was evaluated. Between the two groups, the total number of words, the number of closed and content words and their percentage were significant and lexical richness in spontaneous speech in normal group were significantly higher than those in mentally retarded group (P 02/0=). In addition, the mentally retarded individuals use the number of fewer words, very little lexical diversity also they use more verbs, and then nouns and Fewer closed words to information transmission.