Phoneme monitoring in internal and external speech

Four experiments examine the time course of phoneme monitoring in internally and externally generated speech. The aim of this research was to replicate and extend previous findings of Wheeldon and Levelt (1995), who required their Dutch participants to monitor their own prearticulatory speech in order to investigate the generation of an abstract phonological code. Experiment 1 required British participants to silently generate English words with a CVCCVC structure and to monitor these words for the four constituent consonants. Similar to the Dutch study, a clear left-to-right monitoring effect was observed and a significant difference was seen between latencies for the consonants separated by the initial vowel and for the consecutive word medial consonants. Internal speech monitoring was also found to speed up across the word. A perception version of the task (Experiment 2) yielded a different pattern of monitoring latencies. In Experiments 3 and 4, all phonemes in the initial CVC syllable of bisyllabic words were monitored in internal and external speech respectively. A significant left-to-right pattern of monitoring latencies was again observed in the internal speech task. However, in the external speech task, monitoring latencies for the vowel and final consonant of the syllable did not differ. The conclusions of Wheeldon and Levelt are discussed and refined in light of the present results.