Of course, through learning and education, i.e. through an acquisition of the sciences. It is well known that in Augustine the idea of an ascent to the higher world is inseparably linked to his notion of self-reflection. It is only on the way of self-recognition that humans can advance to the intelligible realm. According to Augustine, reason manifests itself in the world. It does so in two ways, namely in human language and in beauty.
Humans are sociable beings.
Since intellectual intercourse is a precondition of social life, humans invented sounds and bestowed meanings on them by assigning them to things. In Augustine's view, the rationality of language lies in its power of signification. Augustine is aware of the fact that even animals use signs, but he holds that only the capability of inventing and using meaningful words counts as an indication of reason. However, they both are manifestations of reason and, thus, rational in themselves. The sciences are nothing other than the ways in which reason strives for self-apprehension.