The Interlanguage Speech Intelligibility Benefit as Bias Toward Native-Language Phonology

Area of Science:

• Linguistics
• Second Language Acquisition
• Phonetics

Background:

• The Interlanguage Speech Intelligibility Benefit (ISIB) describes how nonnative speakers may be better understood by other nonnative listeners.
• Existing research presents two hypotheses: benefit only with shared native language (matched interlanguage) or even with different native languages (non-matched interlanguage).

Purpose of the Study:

• To evaluate the validity of existing ISIB hypotheses using absolute intelligibility scores.
• To introduce a relative measure for ISIB (R-ISIB) for more insightful evaluation.
• To re-test the ISIB hypotheses using the proposed R-ISIB measure.

Main Methods:

• Survey of published experimental materials on ISIB.
• Analysis of absolute intelligibility scores.
• Calculation and application of a relative ISIB measure (R-ISIB).

Main Results:

• Both restricted (matched interlanguage) and generalized (non-matched interlanguage) ISIB hypotheses are false when evaluated by absolute intelligibility scores.
• The R-ISIB measure supports the restricted hypothesis (benefit only with shared native language).
• The R-ISIB measure rejects the generalized hypothesis (benefit even with different native languages).

Conclusions:

• Absolute intelligibility scores are insufficient for evaluating the ISIB.
• A shared native language biases listeners towards interpreting sounds based on their shared phonology.
• The R-ISIB measure provides a more accurate assessment of the interlanguage benefit, supporting the role of shared linguistic background.