Cacophony

For the club, see Cacophony Society.
Phonaesthetics is the claim or study of inherent pleasantness or beauty (euphony) or unpleasantness (cacophony) of the sound of certain linguistic utterances. Closely related to euphony and cacophony is the concept of consonance and dissonance.
The phrase cellar door has some notoriety as the reputedly most euphonic sound combination of the English language (specifically, when spoken with a British accent).
From this meaning should be distinguished the closely related but different concept of phonaesthesia, which does not refer directly to aesthetic attributes of sound, but to phonetic elements that are inherently associated with a semantic meaning.Firth in 1930 "The phonæsthetic habits and are of general importance in speech." Firth defined a phonaestheme as "a phoneme or cluster of phonemes shared by a group of words which also have in common some element of meaning or function, though the words may be etymologically unrelated."
Sub-phonematic euphony
In most languages, difficult to pronounce phonetic combinations will be adapted to allow more flowing speech, for reasons of ease of pronunciation rather than aesthetics.