Do letters matter? The influence of spelling on acoustic duration

The present article describes a modified and extended replication of a corpus study by Brewer (2008. Phonetic reflexes of orthographic characteristics in lexical representation. Tucson, AZ: University of Arizona PhD thesis) which reports differences in the acoustic duration of homophonous but heterographic sounds. The original findings point to a quantity effect of spelling on acoustic duration, i.e., the more letters are used to spell a sound, the longer the sound's duration. Such a finding would have extensive theoretical implications and necessitate more research on how exactly spelling would come to influence speech production. However, the effects found by Brewer (2008) did not consistently reach statistical significance and the analysis did not include many of the covariates which are known by now to influence segment duration, rendering the robustness of the results at least questionable. Employing a more nuanced operationalization of graphemic units and a more advanced statistical analysis, the current replication fails to find the reported effect of letter quantity. Instead, we find an effect of graphemic complexity. Speakers realize consonants that do not have a visible graphemic correlate with shorter durations: the /s/ in tux is shorter that the /s/ in fuss. The effect presumably resembles orthographic visibility effects found in perception. In addition, our results highlight the need for a more rigorous approach to replicability in linguistics.