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The methods of analysis of human voice are based on the knowledge of speaker individuality. One of basic studies on speaker acoustic characteristics can be found in (Kuwabara & Sagisaka 1995). According to them the voice individuality is affected by the voice source (the average pitch frequency, the pitch contour, the pitch frequency fluctuation, the glottal wave shape) and the vocal tract (the shape of spectral envelope and spectral tilt, the absolute values of formant frequencies, the formant trajectories, the long-term average speech spectrum, the formant bandwidth). The most important factors on individuality are the pitch frequency and the resonance characteristics of the vocal tract, though the order of the two factors differs in different research studies. According to (Scherer 2003) larynx and pharynx expansion, vocal tract walls relaxation, and mouth corners retraction upward lead to falling first formant and rising higher formants during pleasant emotions. On the other hand, larynx and pharynx constriction, vocal tract walls tension, and mouth corners retraction downward lead to rising first formant and falling higher formants for unpleasant emotions. Thus, the first formant and the higher formants of emotional speech shift in opposite directions in the frequency ranges divided by a frequency between the first and the second formant. In practice, the formant frequencies differ to some extent for different languages and their ranges are overlapped. According to (Stevens 1997) the frequency of vibration of the vocal folds during normal speech production is usually in the range 80 ÷ 160 Hz for adult males, 170 ÷ 340 Hz for adult females, and 250 ÷ 500 Hz for younger children. It means that female pitch frequencies are about twice the male pitch frequencies, pitch frequencies of younger children are about 1.5times higher than those of females and about 3-times higher than those of males. As regards the formant frequencies, females have them on average 20 % higher than males, but the relation between male and female formant frequencies is nonuniform and deviates from a simple scale factor (Fant 2004). Emotional state of a speaker is accompanied by physiological changes affecting respiration, phonation, and articulation. These acoustic changes are transmitted to the ears of the listener and perceived via the auditory perceptual system (Scherer 2003). From literature and our experiments follows that different types of emotions are manifested not only in prosodic patterns (F0, energy, duration) and several voice quality features (e.g. jitter, shimmer, glottal-to-noise excitation ratio, Hammarberg index) (Li et al. 2007) but also by significant

Spectral Properties and Prosodic Parameters of Emotional Speech in Czech and Slovak