Analysis of Nonverbal Speech Sounds

Abstract

The nonverbal speech sounds such as emotional speech, paralinguistic sounds and expressive voices newlineproduced by human beings are different from normal speech. Whereas, the normal speech conveys newlinelinguistic message and has clear articulatory description, these nonverbal sounds also carry nonlinguistic newlineinformation but without any clear description of articulation. Also, these sounds are mostly unusual, newlineirregular, spontaneous and nonsustainable. Examples of emotional speech are shouts, happy, anger, sad newlineetc., and of paralinguistic sounds laughter, cry, cough etc. Besides, the expressive voices like Noh voice newlineor opera singing are trained voices to convey intense emotions. Emotional speech, paralinguistic sounds newlineand expressive voices differ in the degree of pitch changes. Another categorisation based upon voluntary newlinecontrol and involuntary changes in the speech production mechanism is also possible. newlineProduction of nonverbal sounds occurs in short bursts of time and involves significant changes in newlinethe glottal source of excitation. Hence, production characteristics of these sounds differ from those newlineof normal speech, mostly in the vibration characteristics of the vocal folds. Associated changes in the newlinecharacteristics of the vocal tract system are also possible. In some cases of normal speech such as trills newlineor emotional speech like shouts, the glottal vibration characteristics are also affected by the acoustic newlineloading of the vocal tract system and system-source coupling. Hence, characteristics of these nonverbal newlinesounds need to be studied from the speech production and perception points of view, to understand better newlinetheir differences from normal speech. newlineExcitation impulse sequence representation of the excitation source component of speech signal has newlinebeen of considerable interest in speech research, in past three decades. Presence of secondary impulses newlinewithin a pitch period was also observed in some studies. This impulse-sequence representation was newlinemainly aimed at achieving low bit-rates of speech coding and higher voice qualit