LingLang Lunch (Lite) (3/7/2018): Kasia Hitczenko (University of Maryland)

Kasia Hitczenko is a graduate student from the University of Maryland. Her research focuses on infants’ acquisition of categories in language.
 

How to use context to disambiguate overlapping categories: The test case of Japanese vowel length

Infants learn the sound categories of their language and adults successfully process the sounds they hear, even though sound categories often overlap in their acoustics. Most researchers agree that listeners use context to disambiguate overlapping categories. However, they differ in their ideas about how context is used. One idea is that listeners normalize out the systematic effects of context from the acoustics of a sound. Another idea is that contextual information is itself an informative cue to category membership, providing top-down disambiguating information. These two ideas have been studied extensively in the literature, but they have mostly been studied using synthesized or carefully controlled lab speech. In this talk, we contrast the efficacy of these two strategies on spontaneous speech, by applying them to the test case of Japanese vowel length. We find that normalizing out contextual variability from the acoustics does not improve categorization, but using context in a top-down fashion does so substantially. This calls into question the role of normalization in phonetic acquisition and processing and suggests that approaches that make use of top-down contextual information are more promising to pursue.