ABSTRACT
In setting a hearing aid, the Speech Intelligibility Index (SII)—the percentage of
speech cues that are audible—tells most of the story but is far from the entire picture.
It can provide information on the various frequency importance bands in different
languages (and thereby which phonemes or speech sounds are important), but it does
not provide information on word-level and sentence-level cues that may be very important
as well. Phoneme-level differences (seen in an SII) could result in a change in the
frequency response and output specification for hearing aids such as an increase bass
response in a language that has a larger number of sonorants than English or an increase
in the frequency response in the 3000-Hz region for those (Slavic) languages that
have palatalization as a distinctive cue. However, word- and sentence-level differences
would not typically be seen in the SII measure and may necessitate changes in various
compression-related parameters. For example, languages such as Japanese that have
a rigid morphological consonant-vowel-consonant structure may necessitate a different
release time for their nonlinear processing to maintain audibility of the quieter
consonants. Sentence-level differences seen for subject-object-verb languages such
as Hindi and Urdu may require increased amplification for soft-level inputs. Specific
recommendations on how to program a hearing aid for many non-English languages are
given, based on their phoneme-, word-, and sentence-level grammatical characteristics.
KEYWORDS
Languages - SVO - SOV - WDRC - release time - SII - hearing aids - program
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Marshall ChasinAu.D. M.Sc. Reg. CASLPO Aud(C)
Doctor of Audiology, Director of Research, Musicians' Clinics of Canada
340 College Street, Toronto, Ontario, Canada M5T 3A9
eMail: Marshall.Chasin@rogers.com
