Listeners’ sensitivity to nasal coarticulation and its interactions with lexical neighborhood density

Previous research has shown that words from dense phonological neighborhoods, thus subject to greater lexical competition, are hyperarticulated (Wright, 2004; Munson and Solomon, 2004) and produced with a greater degree of coarticulation (Scarborough, 2013). The current study investigates listeners’ sensitivity to lexically conditioned degree of nasal coarticulation. If the basis of attested Neighborhood Density (ND) effects is listener-oriented (as suggested by Wright), listeners’ sensitivity to different degrees of coarticulation may be influenced by ND patterns as well. Forty-three native speakers of American English participated in a forced-choice discrimination task. The stimuli consisted of 32 monosyllabic words with nasal codas, and the degree of vowel nasality was natural or artificially increased or decreased. A Generalized Linear Mixed Effects regression was performed on Correct Response with Direction of Manipulation and ND as fixed factors. The model revealed a significant interaction of Direction and ND (p<0.001), where increased nasality was discriminated more correctly among high ND words while decreased nasality was discriminated more correctly among low ND words. This result shows that listeners are indeed sensitive to differences in degree of nasal coarticulation, and in ways that reflect neighborhood conditioned patterns.