Phonetic encoding of infrequent articulatory phonetic transitions

Abstract

Background: The purpose of this experiment was to investigate the underlying mechanisms responsible for the phonetic encoding of novel articulatory speech gestures (i.e., nonwords). Understanding these mechanisms is critical to gain a comprehensive realisation of normal speech production as well as insight into the nature of pathologic speech. Aims: The following research questions were addressed: (1) Is there a significant difference in the response latency among low, moderate, and high interphonemic transitional frequencies in nonwords? (2) Is there a significant difference in the response latency among low and high lexical frequencies in real words? (3) Is there a significant difference in total durations among low, moderate, and high interphonemic transitional frequencies in nonwords? Methods & Procedures: A total of 19 females between the ages of 50 and 79 repeated nonwords that were constructed in three interphonemic transitional frequency categories (low, moderate, high) and elicited in an immediate response condition. Outcomes & Results: The results showed an expected significant difference of shorter response latency for the high‐frequency nonwords when compared to the moderate‐ and the low‐frequency nonwords, and an unexpected significantly shorter duration for the low‐frequency nonwords when compared to the moderate‐ and the high‐frequency nonwords. Conclusions: Results are consistent with the interpretation that the high‐frequency nonwords were initiated immediately (short response latency) and encoded phonetically on‐line during production (longer nonwords duration), while the motor programs for the low‐frequency nonwords were pre‐loaded prior to initiation of production (longer response latency) and executed without update (shorter nonwords duration).