Investigating Emphatic Consonants in Foreign Accented Arabic

This paper investigates the four emphatic consonants of Arabic from the point of view of automatic speech recognition. Comparisons of the recognition error rates for these phonemes and for their non-emphatic counterparts are analyzed in five experiments that involve different combinations of native and non-native Arabic speakers. In addition, the target consonants are described in time-frequency domain analyses. All experiments used the Hidden Markov Model toolkit (HTK) and the Language Data Consortium (LDC) WestPoint Modern Standard Arabic (MSA) database. Results confirm that emphatic consonants are a major source of difficulty for ASR. While the recognition rate for certain emphatic consonants such as /D/ can drop below 15% when uttered by non-native speakers, there are advantages to including non-native speakers in ASR. Regional differences in the pronunciation of MSA by native Arabic speakers require the attention of Arabic ASR research.