The Ink in Our Speech: Influence from Orthographic Complexity in Speech Production

In this dissertation, I present three studies that expand our field’s understanding of the role of orthography in speech production, particularly the interaction between the complexity of an orthographic form and speech duration. The studies address this topic in Japanese, English, and novel words. To the author’s knowledge, there has been no previous research that explores the interaction between the complexity of an orthographic form and speech duration in a language with a non-alphabetic writing system. The results of these studies are presented as evidence that orthographic units beyond letters can influence speech duration, although non-alphabetic orthographic units may interact with speech differently than letters. In the first study I build upon previous research that finds a correlation between spelling and speech duration: The more letters in the orthographic representation of a segment, the longer that segment is produced (Brewer, 2008). Until the time of this study, this effect had only been examined in languages with alphabetic writing systems. I further investigate this behavior in Japanese, a language with a logography. Native Japanese-speaking participants were audio-recorded reading pairs of homophonous words that varied in number of pen strokes or number of whole characters. Two-character words were produced significantly longer than 1-character words, however there was no significant effect from number pen strokes on speech duration.The second study directly expands upon the first study by conducting 5 multi-day novel word learning experiments to investigate the effects on speech production from different measures of orthographic complexity. Each experiment used a novel orthography that varied in the orthographic complexity among homophonous triplets by: a) number of pen strokes; b) number of whole graphemes; c) number of pen strokes and whole graphemes; d) number of repeating sub-graphemic components; e) number of non-repeating sub-graphemic compo