Infants in the early stages of word learning have difficulty learning lexical neighbors (i.e., word pairs that differ by a single phoneme), despite the ability to discriminate the same contrast in a purely auditory task. While prior work has focused on top-down explanations for this failure (e.g. task demands, lexical competition), none has examined if bottom-up acoustic-phonetic factors play a role. We hypothesized that lexical neighbor learning could be improved by incorporating greater acoustic variability in the words being learned, as this may buttress still developing phonetic categories, and help infants identify the relevant contrastive dimension. Infants were exposed to pictures accompanied by labels spoken by either a single or multiple speakers. At test, infants in the single-speaker condition failed to recognize the difference between the two words, while infants who heard multiple speakers discriminated between them.

It is well attested that 14-month olds have difficulty learning similar sounding words (e.g. bih/dih), despite their excellent phonetic discrimination abilities. In contrast, Rost and McMurray (2009) recently demonstrated that 14-month olds’ minimal pair learning can be improved by the presentation of words by multiple talkers. This study investigates which components of the variability found in multi-talker input improved infants’ processing, assessing both the phonologically contrastive aspects of the speech stream and phonologically irrelevant indexical and suprasegmental aspects. In the first two experiments, speaker was held constant while cues to word-initial voicing were systematically manipulated. Infants failed in both cases. The third experiment introduced variability in speaker, but voicing cues were invariant within each category. Infants in this condition learned the words. We conclude that aspects of the speech signal that have been typically thought of as noise are in fact valuable information – signal – for the young word learner.

Background Many children with autism spectrum disorders (ASD) struggle to understand familiar words and learn unfamiliar words. We explored the extent to which these problems reflect deficient use of probabilistic gaze in the extra-linguistic context. Method Thirty children with ASD and 43 with typical development (TD) participated in a spoken word recognition and mapping task. They viewed photographs of a woman behind three objects and simultaneously heard a word. For word recognition, the objects and words were familiar and the woman gazed ahead (neutral), toward the named object (facilitative), or toward an un-named object (contradictory). For word mapping, the objects and words were unfamiliar and only the neutral and facilitative conditions were employed. The children clicked on the named object, registering accuracy and reaction time. Results Speed of word recognition did not differ between groups but varied with gaze such that responses were fastest in the facilitative condition and slowest in the contradictory condition. Only the ASD group responded slower to low frequency than high-frequency words. Accuracy of word mapping did not differ between groups, but accuracy varied with gaze with higher performance in the facilitative than neutral condition. Both groups scored above single-trial chance levels in the neutral condition by tracking cross-situational information. Only in the ASD group did mapping vary with receptive vocabulary. Conclusions Under laboratory conditions, children with ASD can monitor gaze and judge its reliability as a cue to word meaning as well as typical peers. The use of cross-situational statistics to support word learning may be problematic for those who have weak language abilities.

Purpose The purpose of this study was to determine whether citizens with language impairment understand legal rights as conveyed in Miranda warnings. Method Grisso's Instruments for Assessing Understanding and Appreciation of Miranda Rights (1998) was administered to 34 young adults, half of whom met the diagnostic criteria for specific language impairment (SLI). A correlational analysis of the relationship between language scores and Miranda rights comprehension was conducted, as were tests of differences between individuals with SLI (n = 17) and individuals without SLI. Results Language ability was positively correlated with overall performance on the Miranda measure. As a group, individuals with SLI were significantly poorer than their peers with normal language at defining Miranda vocabulary and applying Miranda rights in hypothetical situations. The group with SLI was also marginally less able to paraphrase Miranda sentences. Conclusion Language impairment limits comprehension of Miranda warnings. As a result, citizens with language impairment are at risk of being denied their constitutional rights.