The language of twins allows researchers in language development to examine acquisition in a unique environment. Researchers investigating the nature-nurture controversy, the order of acquisition, and other linguistic features find the twin situation particularly interesting because of the children's shared genetic makeup and environment. A substantial amount of relevant literature is available. Review of this material and analysis of the language samples of a set of fraternal twins give insight into the language development process and reinforce the concept of individual differences in language use and acquisition. Samples of the 3-year-old twins' language used in free conversation, event representations, bedtime routine, parent-child interaction, and child-babysitter interaction were examined for linguistic characteristics, differences, and similarities. Results suggest strongly that individual preferences and personalities shape linguistic performance, and that the children's abilities reinforce the influence of environment on language development. It is concluded that the twin situation is an example of language variation within a single household, in which the linguistic support offered a child must complement his perceptions if abilities are to be developed fully. It also illustrated that parental support for twins during difficult stages is challenging. (MSE)