Schwa’s duration and acoustic position in American English

Is American English schwa’s position determined solely by the context in which it appears? Do vowels neutralize to schwa when their duration is shorter? We address these two inter-related questions using the Buckeye corpus to study vowel behavior across multiple contexts of spontaneous speech. We find that all except tense high vowels shift to lower F1 values when their duration is relatively short, including lax high vowels and lexical schwas, rather than toward a mid-vowel position that schwa occupies when its duration is long. However, we also replicate the finding that schwa is more dependent on both context and duration than other vowels. The results are not consistent with the idea that schwa’s position is determined exclusively by the context in which it appears. However, schwa’s shift to higher F1 values when its duration is longer is not necessarily different from other vowels’ shift to higher F1 values when their duration is longer, making it unnecessary to argue that schwa’s mid-vowel properties are due to having a target in F1 terms.