German and English comparison of fluency development and stuttering
The thesis explored disfluencies in stuttering through linguistic contrasts between English and German. Part one focused on the analysis of speech samples of German speaking adults and children who stutter. Part two analysed bilingual German-English language development aiming to examine whether increased cognitive load of two languages is related to language errors. Since people who stutter do not speak disfluently all the time, but have stretches where speech is fluent, research has investigated whether there is a consistent pattern predicting fluency breakdown (Brown, 1937, 1938a, 1938b, 1938c, 1945; Johnson and Brown, 1939). Inconsistencies across different languages would weaken purely motoric accounts of stuttering. This was analysed with spontaneous speech samples of German speaking people who stutter, from a wide age range (2 years to adult). Previously, mainly in English, an exchange pattern of function and content word disfluencies with age was reported (see Au-Yeung, Howell and Pilgrim, 1998, and Rommel, 2000, for increased function word disfluencies in German children). This pattern was more prominent in German speakers changing from more function words in children to predominantly content word disfluencies in adults. Larger amounts of content word disfluencies in German adults were related to their higher phonetic complexity in comparison to English. Part two of the thesis dealt with factors affecting language development in bilingual infants (language onset to school age) based on the link, identified in the literature, between bilingualism and onset of disfluencies. This part aimed to explore differences in lexical and syntax development (both are influential in the onset of disfluencies in infants who stutter - Bernstein Ratner, 1997), naming errors, and lexical access. The results showed differences concerning the lexicon (i.e. compound nouns - complex content words) and syntax (i.e. word order).The last chapter highlighted aspects of findings that differentiate current models / theories of fluency failure.