“…In fact, several studies have shown that infants, even pre-babblers, readily associate heard “words” with referents, and use these symbols to categorize objects or parts of objects (see Fulkerson and Waxman, 2007; Ferry et al, 2010, and for children of 12 months, MacKenzie et al, 2011). Interestingly, the reports also show that infants are less successful in forming symbolic associations when presented with sounds like intoned [mmm] or sounds that cannot be articulated, and instead attend to familiar speech (MacKenzie et al, 2011; Marno et al, 2015, 2016; and for evidence that activity in language areas of the brain are organized in terms of speech sounds, see Magrassi et al, 2015). This ability to acquire symbols is not distinctly human, as we noted, but communication by way of orally articulated signs is.…”