In search of language-based factors influencing rhythmic grouping

The Iambic-Trochaic Law (Hayes, 1995) was proposed as a universal mechanism governing rhythmic grouping. It predicts that sequences of sound events are grouped trochaically (strong-weak) when they alternate in intensity or pitch, and iambically (short-long) when they alternate in duration (Langus et al., 2016). Previous studies have found native language effects on grouping of both linguistic (Crowhurst & Teodocio Olivares, 2014; Langus et al., 2016) and non-linguistic (Iversen et al., 2008; Molnar et al., 2016) sounds, as they revealed grouping preferences incompatible with the predictions of the ITL. The present study investigated native language effects on rhythmic grouping by presenting native Turkish speakers sequences of tones (Experiment 1A and Experiment 1B) and syllables (Experiment 2). Lack of native language effects on grouping as revealed by the results, was explained by the stress 'deafness' (i. e., reduced sensitivity to stress deviations) exhibited by Turkish speakers, under the assumption that Turkish has predictable, fixed stress. That speakers of languages with fixed, lexically unmarked stress were reported to exhibit similar insensitivities to stress deviations (Dupoux et al., 1997; Peperkamp & Dupoux, 2002; Rahmani et al., 2015; Lu et al., 2018) supported this conclusion.