Ключевые слова: 20s, adult, announcement, blackboard, caucasian, chalkboard, class, classroom, college, communication, education, female, holding, horizontal, indoors, knowledge, learning, lecture, loud, mathematics, megaphone, message, microphone, noise, one, people, person, professor, redhead, screaming, seminar, shouting, side, speaker, speech, student, teacher, university, view, woman, women, yelling, young,