| In the field of spoken language production there are two leading theories, namely the model of spoken language production by Levelt, Roelofs and Meyer (1999) and the connectionist theory of language production proposed by Dell (1986). Levelt et al. describe speech as a serial process, meaning that there is no interaction between the consecutive stages in the model. In contrast, Dell assumes that there is interaction between the stages in his model. Therefore, the interactivity between the stages in speech production is an important difference between the two models. Several phenomena deal directly with this interactivity. Two of such phenomena are phonological neighborhood density and phonological neighborhood frequency. Phonological neighbors are words that differ by only one phoneme which can be substituted, added or omitted. Phonological neighborhood density refers to the number of phonological neighbors a certain target word has. Phonological neighborhood frequency is the mean frequency of the phonological neighbors of a certain target word. It is found that English subjects respond faster and make fewer errors to words with many phonological neighbors and a high frequent neighborhood than to words with few phonological neighbors and a low frequent neighborhood (Vitevitch, 2002; Vitevitch & Sommers, 2003). These effects can be explained if one assumes that a word with many phonological neighbors receives more feedback activation (from its neighbors) then a word with less phonological neighbors. In other words, the effect can be explained if the interactivity between the stages of language production is assumed. The same reasoning holds for the phonological neighborhood frequency effect. |
