The articulation of derived affrication in American English

Affrication of coronal stops before /ɹ/ is commonly observed in English. For instance, /t/ in “tree” and /d/ in “dream”, in which coronal stops precede /ɹ/, are often realized as affricated stops (i.e., [ɹi] instead of [tɹi]; [ɹim] instead of [dɹim]). Given that morphological structures and frequency of words play a critical role in many coarticulatory processes (Bush, 2001; Ernestus et al., 2006; Myers and Li, 2009), the present study investigates whether the degree of derived affrication before /ɹ/ is influenced by different morphological structures and frequency of words and phrases. This study uses ultrasound imaging and audio recordings of seven native speakers of American English to examine the articulatory aspect of derived affrication. Comparisons of the degree of affrication show significant differences among words in various environments, in which tautomorphemic words and high-frequency words and phrases lead to greater degree of affrication. Furthermore, the gestural patterns of various morphological and frequency conditions are highly individualized.