Speaking and Misspeaking

Dell 1995

Dell gives a general description of speech errors, and discusses the conclusions that we can make about speech generation from those errors. After some introductory discussion, he categorizes speech errors into different levels and types. In particular, he asserts that speech errors can occur at the level of the clause, phrase, word, morpheme, syllable, rhyme, consonant cluster, phoneme, or phonological feature; and gives several different types of speech error, such as exchange, noncontextual substitution, shift, anticipation, and preservation.

Dell argues that the fact that speech errors occur at the levels that they do provides us with solid evidence that those levels (which were posited for independant reasons) actually reflect specific aspects or encodings in the cognitive system responsible for generation.

Based on the distribution of word errors, Dell argues that some aspects of speech generation rely on retrieval, while others rely on generation. In particular, he asserts that most speech errors arise from problems in generation. Since generation is a productive task, it is prone to swap or re-use elements, etc., which can account for many of the errors we see. So Dell argues that word combination and phoneme combination (and maybe morpheme combination) are productive (generative) tasks, while the other levels (phrases, phonological features, etc) are based on retrieval.

Dell describes a class of computational models that can account for the kinds of errors that people make, called spreading activation models. In these network-based models, syntax trees are connected to words that might fill them in; and words are connected to phonemes that realize them. Sentences are generated by increasing the activation of the appropriate elements. The strongest connections are the ones that are used. (There must also be some aspect of competition between nodes, but it's not directly discussed.) Speech errors are caused when a word or phoneme gets associated with the wrong structure.

@InCollection{dell1995,
  author =       {Gary Dell},
  title =        {Speaking and Misspeaking},
  booktitle =    {An Invitation to Cognitive Science},
  pages =        {183-208},
  publisher =    {MIT Press},
  year =         1995,
  editor =       {Lisa R. Gleitman and Mark Liberman},
  volume =       1,
  chapter =      7,
  edition =      2
}