Analysis of Phonetic Level Similarities Across Languages in Emotional Speech

Unsupervised domain adaptation offers significant potential for cross-lingual speech emotion recognition (SER). Most relevant studies have addressed this problem as a domain mismatch without considering phonetical emotional differences across languages. Our study explores universal discrete speech units obtained with vector quantization of wavLM representations from emotional speech in English, Taiwanese Mandarin, and Russian. We estimate cluster-wise distributions of quantized wavLM frames to quantify phonetic commonalities and differences across languages, vowels, and emotions. Our findings indicate that certain emotion-specific phonemes exhibit cross-linguistic similarities. The distribution of vowels varies with emotional content. Certain vowels across languages show close distributional proximity, offering anchor points for cross-lingual domain adaptation. We also propose and validate a method to quantify phoneme distribution similarities across languages.