phonaesthetics

Euphony is the demonstration of pleasant phonaesthetics.

Cacophony is the demonstration of unpleasant phonaesthetics, or unpleasant, discordant sounds.

Tolkien also discusses phonaesthetics, citing Greek, Finnish, and Welsh as examples of "languages which have a very characteristic and in their different ways beautiful word-form".

In the final part of the lecture, Tolkien explores the concept of phonaesthetics, citing the phrase cellar door as a recognized beautiful-sounding phrase in English, adding that to his own taste, in Welsh "cellar doors are extraordinarily frequent".