This longitudinal study investigated the acquisition of question formation in spoken English and American Sign Language (ASL) by two young hearing children of deaf parents. The linguistic environment of the children included varying amounts of exposure and interaction with normal speech and with the nonstandard speech of their deaf parents. This atypical speech environment did not impede the children's acquisition of English question forms. The two children also acquired question forms in ASL that are similar to those produced by deaf children of deaf parents. The two languages, ASL and English, developed in parallel fashion in the two children, and the two systems did not interfere with each other. This dual language development is illustrated by utterances in which the children communicated a sentence in spoken English and ASL simultaneously, with normal English structure in the spoken version and sign language structure in the ASL version.