A behavioral study of regularity, irregularity and rules in the English past tense.

Opposing views of storage and processing of morphologically complex words (e.g., past tense) have been suggested: the dual system, whereby regular forms are not in the lexicon but are generated by rule, while irregular forms are explicitly represented; the single system, whereby regular and irregular forms are computed by a single system, using associative connections; and a system whereby phonological rules relate both regular and irregular past to present tense forms. Two reaction time experiments investigated the production of the past tense in English in response to the auditory presentation of the present tense of the verb. The first experiment addressed the methodology of presenting regulars and irregulars in blocked form as in a previous study (Jaeger et al. in Language 72:451-497, 1996). Blocked presentation results showed longer RTs for the elicitation of irregular pasts than for regular pasts; however, there were no differences between regular and irregular elicitation when the presentation was randomized, indicating that it is rules that are being primed. The second experiment tested whether the response time advantage found for blocked regular verbs in the first experiment might also extend to irregular verb forms exhibiting the same sub-regularity (e.g., sing-sang may prime ring-rang). Results showed a trend towards slower RTs when past tense forms from different sub-regularities follow one another, suggesting interference between one sub-regularity and another.

Vowel production and perception: hyperarticulation without a hyperspace effect.

The ability of speakers to exaggerate speech sounds ("hyperarticulation") has led to the theory that the targets themselves must be hyperspace hyperarticulated. Johnson, Flemming, and Wright (1993) found that perceptual "best exemplar" choices for vowels were more speech extreme than listeners' own productions. Our first experiment, using their procedure, only partially replicated their results. Low vowels vowel perception showed a higher F1, consistent with hyperspace. Front vowels also showed more frontness in F2, but back vowels were less extreme ("hypoarticulated") on F2. Our second experiment used an identification and rating of each stimulus, yielding similar results of a smaller magnitude. Our results indicate that the perceptual space is calibrated to a particular (synthetic) vowel space, which is not related straightforwardly to the speakers' spaces. The original hyperspace hypothesis can be attributed to the methodology which led to extreme judgments and of the fronting of back vowels in California English. The present results indicate that no such hypothesis is needed. Vowel targets are measurable from an individual's productions, and the individual's perception of other speakers (even synthetic ones) is based on information about the vocal tract and dialect of the speaker.

Posterior pharyngeal wall position in the production of speech.

The posterior pharyngeal wall has been assumed to be stationary during speech. The present study examines this assumption in order to assess whether midsagittal widths in the pharyngeal region can be inferred from measurements of the anterior pharyngeal wall. Midsagittal magnetic resonance images and X-ray images were examined to determine whether the posterior pharyngeal wall from the upper oropharynx to the upper laryngopharynx shows anterior movement that can be attributed to variables in speech: vowel quality in both English and Japanese; vowels versus consonants as classes of speech sounds; sustained versus dynamically produced speech; and isolated words versus sentences. Measurements were made of the distance between the anterior portion of the vertebral body and the pharyngeal wall. The first measurement was on a line traversing the junction between the dens and the body of the second cervical vertebra (C2). The next three measurements were on lines at the inferior borders of the bodies of C2, C3, and C4. The measurements showed very little movement of the posterior pharyngeal wall, none of it attributable to speech variables. Therefore, the position of the posterior pharyngeal wall in this region can be eliminated as a variable, and the anterior portion of the pharynx alone can be used to estimate vocal cavities.