Human infants understand communicative intentions pre linguistically,

The human adaptation for shared intentionality emerges ontogenetically at around the first birthday as two developmental pathways come together: (1) the general primate social-cognitive ability to understanding the goals and perceptions of others (and perhaps the intentions and attention of others); and (2) the uniquely human skills and motivations for sharing psychological states with others. As these two strands come together, human infants become able to create shared goals and intentions with others in joint action, and also to engage in various kinds of joint attentional activities, which create the ability to understand multiple perspectives on a common entity. The difference between humans and apes can be most clearly seen when their behavior is compared in situations involving helping (which do not involve full-blown shared intentionality, and in which they differ only a little) and situations involving true co-operation and shared intentions (in which they differ more profoundly). This same basic difference emerges when humans and apes are compared in the comprehension of communicative intentions (e.g., as expressed in both deictic and iconic gestures): human infants understand co-operative communicative intentions prelinguistically, whereas apes do not understand these at all - but rather understand the (social) intentions of others most readily in competition.