A preliminary study of speech motor learning was completed in normal adults with no history of developmental or acquired speech disorders. English sounds were combined into two novel meaningless """"""""words"""""""" with some sound combinations that violated English phonotactic rules. The meaningless words were presented via audio tape with novel idiographic symbols. A sequence of taped presentations which modeled the words provided a distraction task and tested recall in response to the idiographic symbol, was repeated 9 times. Two final test trials without modeling were presented for each word. Learning curves differed between the two words: the word involving more lingual articulations was more difficult. The ease of learning was significantly greater for sound combinations that did not violate English phonotactic rules. Preliminary examination of lip, jaw and tongue movement patterns during speech learning suggested that as speech accuracy increased, the movement pattern became further detailed suggesting that speech movement patterns are not learned as sequential items but rather as a whole template with increasing differentiation. A more complete study will be conducted this year. A comparison of speech motor learning in adults who stutter and control subjects demonstrated that those who stutter were significantly impaired in their rate and accuracy of speech motor learning. Learning curves were not found in the adults who stuttered on either of the two words. On one of the two words, none of the adults who stutter achieved the normal range of accuracy of sound production on the final two test trials. Finally, the sound errors in the adults who stutter were high not only on sound combinations that violated English phonotactic rules, but also on vowel sounds between acceptable English sound combinations. This is a preliminary study but the results suggest that adults who stutter are not only impaired in speech motor learning but also use different learning strategies than control subjects.
