these results show that at the age of 6 months infants are sensitive to how often certain sounds occur in the language they are exposed to and they can learn which cues are important to pay attention to from these differences in frequency of occurrence. in natural language exposure this means typical sounds in a language (such as prevoiced /d/ in spanish) occur often and infants can learn them from mere exposure to them in the speech they hear. all of this occurs before infants are aware of the meaning of any of the words they are exposed to, and therefore the phenomenon of statistical learning has been used to argue for the fact that infants can learn sound contrasts without meaning being attached to them.