Syllt for building deltas: Simple speech synthesis for teaching and research

Syllt is a new computer software tool for speech synthesis on PCs and Sun workstations. Using the Delta System [Hertz, PapersinLaboratoryPhonologyI (1990)], Syllt implements a phone-to-speech rule set that synthesizes high-quality CVC syllables from a string of phones entered by the user. The program allows rapid creation of synthetic stimuli for perception experiments, and provides a tool for teaching acoustic phonetics. In the process of creating speech output, Syllt produces a multi-tiered utterance representation (a ‘‘delta’’) that coordinates phonological units (such as phonemes), phonetic units (such as bursts), and quantitative parameter values (such as formant frequencies) for a Klatt synthesizer. Users can interactively manipulate the value and relative timing of any of these elements—for example, timing of voicing relative to stop release, amplitude and frequency of burst noise, or formant trajectories. The result of any change can be immediately heard and evaluated. Delta manipulation can be easily automated to generate continua of stimuli that differ along one or more dimensions. The user has access to the rule set itself, which is extensively documented and can be customized for particular research needs. The structure and performance of Syllt will be demonstrated. [Work supported by NIH.]