phonaesthetic

Exhibiting phonaesthesia.

In addition to the history of cultural stereotyping, which certainly plays a role, it’s the comparison of entire sound systems that produces a phonaesthetic character in the mind of the listener: the sounds present, the way they’re combined, the intonational phrasing, and the rate of speech—plus a number of sociological factors.

Euphonious.

Of or relating to phonaesthetics (aesthetics of phonology).

Indeed, if there is anything at all to phonaesthetics, there must be some nonarbitariness to phonetic structure -- at least to people who have some phonaesthetic perceptions (as people on this list have admitted they have), if not to everyone.