"This is moistened by most of the flavors, but is also made drier by some: for instance by pepper and salt-fish and numerous other things which, although they are tastable, have a drying effect; not because they are succulent but through some tangible quality like dryness or warmth. For dry bread does not make [the tongue] dry -- or if one should encounter crumbs and something similar -- but by being dry or warm it makes the moist quality in the tongue get wet. Evidence that it is necessary that the tongue be moist in potential but not in actuality: those who have tongues that are excessively dry or moist are unable to perceive tastes. And this is the reason why the tongue that is too moist does not perceive flavors, because the moistness in it, being juicy, strikes it first and becomes the very sense of touch of the tongue, providing perception of itself; in this way it does not allow perception of something from outside. Evidence of this: that those who have first tasted another flavor, even a very strong one, no longer perceive those that follow in the same way."[1]
"Nature made the tongue for two tasks, of which one contributes to the being of those that have it, namely the sense of taste and the ability to distinguish among the flavors; but the other [contributes] to well-being, that is, [the capacity] for communication. Thus also it created two tasks for respiration: the first for being, for it contributes to the cooling of internal warmth; but additionally for well-being, namely communication. Of this, as it is necessary, it is a work of nature and a cause of survival. The exhaled air [is] the medium of speech. The productive cause [is] nature, the instrumental [cause] the rough windpipe; for it is like a reed-pipe. Of course younger people have a more pleasant voice since it [sc. the windpipe] is smooth, but old men have a more unpleasant voice since theirs is rougher. But the final cause [is] signification: for the purpose of the voice for an animal [is] to signify through it the dispositions of the soul. Of communication speech [is] the medium, the rational soul the productive cause, the tongue and the upper parts and the teeth the instrumental cause, and the final [cause] the signification of thoughts. The instrument of the voice [is] the pharynx."[2]
"Those of the birds whose tongues and jaws are arranged in a way similar to those of humans are able to imitate conversation; the jays and parrots and suchlike, for instance."[3]