The goal of the study was to describe perceptual and acoustic characteristics of emotional spontaneous speech of adolescents aged 14–16 years. 18 adolescents aged 14–16 years (9 boys and 9 girls, three people in each age) were participants. Perceptual analysis of speech of children by adults (70 Russian speakers and 70 speakers of other languages) was conducted to define the emotional state via voice and speech characteristics. Instrumental and linguistic analysis was used to determine acoustic features and linguistic information on which listeners rely while recognizing the adolescents’ state. It was shown that listeners had difficulty in recognizing the emotional state of adolescents, but Russian-speaking listeners recognized the emotional state better (26% of phrases recognized with probability 0.75–1.0) than speakers of other languages. Adults recognized comfort better than discomfort, Russian listeners better than foreigners. Russian listeners are likely to rely on acoustic and linguistic information, speakers of other languages – on acoustic features of adolescents’ speech. Phrases uttered in comfort are characterized by a wider pitch range vs. phrases uttered in the neutral state. It was revealed that the phrases of girls uttered in comfort have significantly higher average pitch values vs. discomfort. There were no significant differences between boys and girls in acoustic characteristics of emotional speech. Phrase duration and pitch range values can be included in automatic recognition systems of the speaker’s emotional state via speech as additional informative features. The paper discusses the specificity of emotion manifestation in adolescents and the possibility of further use of the results.