The onset of intentional communication late in the first year of life marks an infant's active entry into his or her culture and ignites important changes in how others regard and respond to the infant. A significant delay in the onset of intentional communication is a strong indicator that the onset of productive language also will be delayed (McCathren, Warren, and Yoder, 1996; Calandrella and Wilcox, 2000). Such a delay may hold the infant in a kind of developmental limbo because the onset of intentional communication triggers a series of transactional processes that support the emergence of productive language just a few months later. In this article we discuss the research on the effects of prelinguistic communication interventions aimed at teaching infants and toddlers with developmental delays to be clear, frequent prelinguistic communicators.

The onset of coordinated attention occupies a “pivotal” juncture in prelinguistic communication development. Before the emergence of coordinated attention, an infant's intention is very difficult to discern (Bates, Benigni, Bretherton et al., 1979). Almost simultaneously with the emergence of coordinated attention, the child begins to move from preintentional to intentional communication. Requesting and commenting episodes provide the earliest contexts in which intentionality is demonstrated (Bates, O'Connell, and Shore, 1987). Both functions require the infant to shift his or her attention between his or her partner and an object. Requesting (also termed imperatives and protoimperatives in the literature) is commonly defined as behavior that clearly indicates that the child wants something. Commenting (also termed joint attention, indicating, declarative, and referencing in the literature) is the act of drawing another's attention to or showing a positive affect about an object or interest (Bates, Benigni, Bretherton et al., 1987). Although other communicative functions also emerge during this period (e.g., greeting, protesting), requesting and commenting are considered the fundamental pragmatic building blocks of both prelinguistic and linguistic communication (Bruner, Roy, and Ratner, 1980). They are also the two most frequent functions expressed during the prelinguistic period (Wetherby, Cain, Yonclas et al., 1988).