The development of the listening in spatialised noise - universal test (LiSN-U) and preliminary evaluation in English-speaking listeners.

Objective: To create a language independent version of the Listening in Spatialised Noise - Sentences test (LiSN-S) and evaluate it in an English-speaking population.Design: Test development and normative data collection. LiSN-Universal (LiSN-U) targets consisted of CVCV pseudo-words (e.g. /mupa/). Two looped distracter tracks consisted of CVCVCVCV pseudo-words. The listener's task was to repeat back the target pseudo-words. Stimuli were presented over headphones using an iPad. Speech reception thresholds were measured adaptively. In the co-located condition all stimuli came from directly in front. In the spatially-separated condition the distracters emanated from +90° and -90° azimuth. Perceived location was manipulated using head-related transfer functions. Spatial advantage was calculated as the difference in dB between the co-located and spatially separated conditions.Study samples: Stimulus intelligibility data were collected from 20 adults. Normative data were collected from native English speakers (23 adults and 127 children).Results: Children's spatially separated, co-located, and spatial advantage results improved significantly with age. Spatial advantage was 4-6 dB larger in the LiSN-U than LiSN-S depending on age group.Conclusion: Whereas additional research in non-native English populations is required, the LiSN-U appears to be an effective tool for measuring spatial processing ability.

Cluster reduction and compensatory lengthening in the acquisition of possessive -s.

Previous research shows that two-year-olds' third person singular -s and plural -s are produced more accurately in utterance-final compared to utterance-medial position. However, only the third person singular is affected by coda complexity. This study explores these effects with possessive -s. Acoustic analysis of twelve two-year-olds' elicited imitations examined the use of simple versus complex codas (e.g. Sue's vs. Doug's ) both utterance-medially and utterance-finally. Morpheme production was surprisingly robust across contexts, though coda clusters were often simplified to a lengthened -s morpheme utterance-medially (e.g., Dou's [dɐz]). The findings raise many questions about the development of speech planning processes across populations.