What Speech Errors Can Tell Us About Word-Form Generation: The Roles of Constraint and Opportunity

The likelihood of occurrence of a speech error is influenced by constraints imposed on the word-form generation process as well as by characteristics of the words in the utterance. In three tongue twister experiments I investigated these roles of constraint and opportunity. In Experiments 1 and 2 word onsets were more likely to interact with each other in a speech error than with phonemes in other positions. However, phonemes in word-internal positions were less likely to interact with each other than with word onsets. These results indicate that word onsets are particularly error-prone and therefore often interact with each other, but are also very likely to engage in interactions with phonemes in other positions if the elicitation technique encourages these interactions. The fatal experiment aimed to create speech errors in which consonants and vowels interacted. These errors are rarely reported in the literature but were successfully generated in this experiment. The implications for a model of word-form generation are discussed.