Language Dependency of /s/ Production: Native Dutch Versus Non-Native English

Area of Science:

• Phonetics
• Forensic Linguistics
• Acoustic Phonetics

Background:

• Forensic recordings increasingly involve multiple languages.
• The voiceless alveolar fricative /s/ is acoustically similar in Dutch and English.
• This phonetic similarity suggests potential for language-independent analysis in forensic speaker comparisons.

Purpose of the Study:

• To investigate the language dependency of the /s/ sound in native (L1) Dutch and non-native (L2) English speakers.
• To assess the acoustic stability of /s/ across languages for forensic speaker identification.
• To determine the influence of phonetic context on the language dependency of /s/.

Main Methods:

• Analysis of spectral moments (center of gravity, standard deviation, skewness, kurtosis) of the /s/ sound.
• Comparison of acoustic features between L1 Dutch and L2 English speakers.
• Examination of /s/ tokens in different phonetic contexts, including labial neighbors.

Main Results:

• Standard deviation (SD) of /s/ acoustics remained stable across languages.
• Center of gravity, skewness, and kurtosis of /s/ were language-dependent.
• Language dependency for skewness and kurtosis decreased with a labial phonetic neighbor.

Conclusions:

• The /s/ sound exhibits significant language dependency between L1 Dutch and L2 English speakers.
• Acoustic features of /s/, except for SD, are not reliable for cross-linguistic forensic speaker comparisons.
• Contextual phonetic environment can mitigate but not eliminate language dependency in /s/ acoustics for forensic applications.