Why do people gesture while talking? What is the function of the gestures that accompany speech? Are they informative? One of the first scholars to raise similar questions was American psychologist David McNeill, who stated that gesturing during speech is determined by a common speech and gesture system. According to McNeill (1985), 90% of gestures used by adults are performed exclusively during speech. In addition, gestures are used not only by adults but also children who are yet to acquire language (McNeill, 1992). Studies confirm that the use of gestures is common in all cultures (Feyereisen, de Lannoy, 1991; Iverson, Thelen, 1999), and the main function of it is to convey information to the interlocutor (Kelly et al., 2003; Goldin-Meadow, 2006; Özyürek et al., 2008; Theakston et al., 2014) and reduce the working memory load (Goldin-Meadow et al., 2001; Wagner et al., 2004). Today, most researchers agree that speech and gesture systems are closely related. The latter is confirmed by many empirical studies in experimental psychology, developmental psychology, psychophysiology, linguistics, and cognitive sciences. Speech-accompanying gestures are studied in children (Bates et al., 1989; Alibali et al., 2000; Iverson, Goldin-Meadow, 2005; Theakston, 2014), adults (Langton et al., 1996; Kelly et al., 2003; Chu, Hagoort, 2014), and during child-adult interactions (Iverson, Goldin-Meadow, 1998; Cartmill 2010). Scientists attempt to understand how gestures and speech interact not only in neurotypical but also neurodiverse individuals affected by blindness (Iverson and Goldin-Meadow, 1998), deafness (Goldin-Meadow, 2006), Down syndrome (Iverson 2003), and aphasia (Hanlon, 1990; Pashek, 1997). Although it is agreed that speech and gestures are closely related components of spontaneous communication, there is no consensus on the psychological, biological, and social aspects of their interactions. Also, there is a lack of a unified theoretical approach to the relationship between speech and gesticulation (McNeill, 1985; Feyereisen, 1987; Krauss et al., 1991; Morrel-Samuels, Krauss 1992; Alibali et al. 2000; Theakston et al., 2014). Thus, this study aimed to discuss the impact of speech-gesture interaction on language production and comprehension in neurotypical children and adults. The theoretical discussion is based on the results and conclusions of studies conducted in various fields of psychology.