http://jimflege.com/files/Flege_Schirru_interaction_between_SC_2003.pdf

Interaction between the native and second language phonetic subsystems

The development of phonemic categorization in children aged 6–12

The development of phonemic categorisation in children aged 6 to 12.

The five experiments presented here examine the ability of listeners to detect a foreign accent. Computer editing techniques were used to isolate progressively shorter excerpts of the English spoken by native speakers of American English and French. Native English‐speaking listeners judged the speech samples in one‐ and two‐interval forced‐choiced tests. They were able to detect foreign accent equally well when presented with speech edited from phrases read in isolation and produced in a spontaneous story. The listeners accurately identified the French talkers (63%–95% of the time) no matter how short were the speech samples presented: entire phrases (e.g., ‘‘two little dogs’’), syllables (/tu/ or /ti/), portions of syllables corresponding to the phonetic segments /t/, /i/, /u/, and even just the first 30 ms of ‘‘two’’ (roughly, the release burst of /t/). Both phonetically trained listeners familiar with French‐accented English and unsophisticated listeners were able to accurately detect accent. These results suggest that listeners develop very detailed phonetic category prototypes against which to evaluate speech sounds occurring in their native language.

https://jimflege.com/files/Flege_French_accent_JASA_1984.pdf

The detection of French accent by American listeners

The ability to integrate and weight information across dimensions is central to perception and is particularly important for speech categorization. The present experiments investigate cue weighting by training participants to categorize sounds drawn from a two-dimensional acoustic space defined by the center frequency (CF) and modulation frequency (MF) of frequency-modulated sine waves. These dimensions were psychophysically matched to be equally discriminable and, in the first experiment, were equally informative for accurate categorization. Nevertheless, listeners' category responses reflected a bias for use of CF. This bias remained even when the informativeness of CF was decreased by shifting distributions to create more overlap in CF. A reversal of weighting (MF over CF) was obtained when distribution variance was increased for CF. These results demonstrate that even when equally informative and discriminable, acoustic cues are not necessarily equally weighted in categorization; listeners exhibit biases when integrating multiple acoustic dimensions. Moreover, changes in weighting strategies can be affected by changes in input distribution parameters. This methodology provides potential insights into acquisition of speech sound categories, particularly second language categories. One implication is that ineffective cue weighting strategies for phonetic categories may be alleviated by manipulating variance of uninformative dimensions in training stimuli.

/pdf/cue-weighting-in-auditory-categorization-implications-for-5arg56xa3d.pdf

Cue weighting in auditory categorization: implications for first and second language acquisition.

Three experimental groups consisting of ten four-year-olds, ten 11-year-olds, and ten adults were presented with tape-recorded voiceless stop + vowel syllables and subsyllabic segments isolated fro...

Maturational Influences on Perception of Coarticulatory Effects

Speech timing strategies in elderly adults

Perception of oral diadochokinetic performances in elderly adults

A protocol based on target levels, referenced to maximum voluntary closing force (MVCF), was used to assess static force control in the perioral musculature. Twenty normal-speaking subjects were in...

A maximum-force-dependent protocol for assessing labial force control.

Forty speech-language pathologists listened to randomised recorded samples of the ‘Grandfather Passage' read aloud by 10 normal elderly male adults, 10 normal young male adults and 6 dysarthric subjects. The speech samples were rated according to the 38 dimensions devised by Darley and colleagues for the study of the dysarthrias. The ratings of the speech of the older adults fell significantly further from ‘normal' on a seven-point continuum than those given to the young adults on nine of the dimensions. The most apparent young/old differences involved laryngeal dimensions. Ratings for the normal geriatric subjects resembled those of the dysarthric groups in some respects. Several instances of misclassification of the normal elderly individuals as ‘dysarthric' were also observed.

James D. Amerman

Papers

Maturational Influences on Perception of Coarticulatory Effects

Speech timing strategies in elderly adults

Perception of oral diadochokinetic performances in elderly adults

A maximum-force-dependent protocol for assessing labial force control.

Auditory impressions of the speech of normal elderly adults.