The phonetics of hyper-active feet : effects of stress priming on speech planning and production

This study employs a stress priming paradigm to investigate sensitivity to metrical structure in speech planning and production in Australian English. Target words with iambic stress were preceded by primes with either congruent or incongruent stress and also embedded in metrical contexts biased towards either persistent foot types (Experiment 1) or variable foot types (Experiment 2). Both naming, latency, the time from stimulus presentation to the onset of speech, and phonetic patterns showed sensitivity to metrical manipulations. The paradigm produced stress errors, iambic targets produced as trochees, and variation in vowel formants and syllable duration as a function of metrical context. Patterns in the reaction time data indicated sensitivity to global metrical biases calculated over feet. When the metrical bias was toward persistent feet, iambs were produced more quickly in the congruent stress context. When the metrical bias was reversed, iambs were produced more quickly in the incongruent stress context. This pattern of results supports a speech production model that represents metrical structure and allows competition at the metrical level to influence phonetic variability.