The theme of this study is the communicative behavior of twins with language disorders before and after speech therapy. Data from two pairs of male twins with a diagnosis of language delay were analyzed (monozygotic – S1/S2, dizygotic – S3/S4). Data were collected in assessments made pre and post speech-language audiology intervention through: semi-structured interviews with the parents, observation of communicative behavior, and language and development scale test. The speech-language audiology intervention lasted for 34 months for S1/S2 (from two years and five months to five years and three months) and 17 months for S3/S4 (from three years and seven months to five years and four months). More severe pre, peri and post natal complications with a greater psychomotor and communicative impairment were observed in the pre speech-language audiology intervention assessment. S3/S4 showed less severe pre, peri and post natal complications and development delay occurring only in language. The age of the children in post intervention assessment was similar, however, the pair S1/S2 showed a more damaged global and communicative development, even having received a longer speech-language audiology intervention. S3 showed a performance approximate to the typical development and S4 had difficulties just concerning phonology and pragmatics. The experiences of twins, differentiated as to interpersonal circumstances, lead to atypical language development, due to the reduced objective need of linguistic interaction. The post natal complications in S1/S2 exacerbated the delay in child development, encompassing the communicative development.