Of interest in the current study was how voice inset time (VOT) was influenced by changes in speaking rate across Spanish and English. Three groups of subjects (English monolinguals, Spanish monolinguals and early Spanish-English bilinguals) produced sentences containing voiced and voiceless bilabial stops at different speaking rates. As in previous research, English monolinguals showed rate-dependent effects on their VOT productions: VOT increased as speaking rate decreased. Spanish monolinguals showed a large effect of speaking rate on the duration of prevoicing of the voiced stops. However, they showed only a small effect of rate on the VOT of their voiceless stops. The bilinguals produced VOT values in each language that were nearly identical to their monolingual counterparts. The results from this study indicate that short-lag stops experience minimal variation as a function of speaking rate regardless of the other contrasting phonetic categories within a particular language. In addition, early bilinguals showed evidence of separate representations for voiced and voiceless stops for English and Spanish.

No abstract

The cerebral localization of multiple languages is a topic of active research. This study presents a method for assessing whether partial overlap of active voxels reflects differential language localization, or simply the variability known to occur with multiple runs of the same task in fMRI studies. Two groups of bilingual subjects (early and later learners of L2) performed word fluency and sentence generation tasks in both languages. The degree of separation for regions of activation did not exceed that associated with run-to-run variability for either task or either group. Early bilinguals, however, showed greater total numbers of active voxels than Late bilinguals for both tasks. This effect occurred despite a lack of a behavioral performance differences by the two groups.

The present investigation provides a longitudinal study of an individual (RB) with acquired alexia following left posterior cerebral artery stroke. At initial testing, RB exhibited acquired alexia characterized by letter-by-letter (LBL) reading, mild anomic aphasia, and acquired agraphia. Repeated measures of reading accuracy and rate were collected for single words and text over the course of one year, along with probes of naming and spelling abilities. Improvements associated with natural recovery (i.e., without treatment) were documented up to the fourth month post onset, when text reading appeared to be relatively stable. Multiple oral reading (MOR) treatment was initiated at 22 weeks post-stroke, and additional improvements in reading rate and accuracy for text were documented that were greater than those expected on the basis of spontaneous recovery alone. Over the course of one year, reading reaction times for single words improved, and the word-length effect that is the hallmark of LBL reading diminished. RB's response to treatment supports the therapeutic value of MOR treatment to in LBL readers. His residual impairment of reading and spelling one-year post stroke raised the question as to whether further progress was impeded by degraded orthographic knowledge.

How verbal information is processed and recalled appears to be influenced by the structure of the information presented (e.g., unrelated sentences vs. narratives) and the processes the listener uses to encode the information (e.g., verbatim encoding vs. gist extraction). Twenty adults, half with a history of learning disabilities (HLD) and half without (control group) received functional magnetic resonance imaging (fMRI) scans. Participants were instructed to listen to narrative passages for either the exact wording or the general meaning of the narratives and respond to questions about the narratives. These conditions were contrasted with listening to randomly arranged sentences. Adults in the HLD group responded to test questions less accurately than the control group. Likewise, the HLD group showed physiological differences during both narrative and sentence processing in comparison to the control group. Both groups showed differences in processing narratives for gist versus verbatim information, which involved activation centered over the right precentral sulcus. The results support the notion that distinct aspects of verbal processing draw differentially on a distributed physiological network and that adults selected for HLD show both behavioral and physiological differences on narrative processing tasks. However, these differences are not necessarily qualitative in nature.