Modality interactions of speech and signing in simultaneous communication

This study addresses speech and signing interaction during simultaneous communication (SC). Productions of sentence stimuli by ASL-English bilinguals (CODAs) and signed English (SE) users who know no ASL (SIMCOMs) were compared in two conditions (speech-alone or signing-alone, speech and signing combined). Speech took longer combined than alone, whereas SE took longer alone than combined. The increased duration of speech-combined resulted from increased syllable duration, number of gaps, and gap duration. Rate of signing had a significant effect on speech duration. The decreased duration of signed sentences combined resulted from decreased sign duration, decreased gap duration, and increased sign omissions. Knowledge of ASL was reflected in qualitative differences between the two groups. Sign omissions were analyzed by grammatical category; these are discussed in terms of context-supported permissible deletions and the compensatory use of ASL nonmanual marking devices.