Vocable
In speech, a vocable is an utterance, term, or word that is capable of being spoken and recognized. A non-lexical vocable is used without semantic role or meaning, while structure of vocables is often considered apart from any meaning. A vocable consists of one or a sequence of phonemes and may be represented by a string of letters or other symbols.
Non-lexical vocables are often used in music as artistic content. As common speech disfluencies in many languages, they have little formal meaning and are rarely purposeful.
They are also used in experiments in cognitive psychology; examples from this context are the nonsense syllables introduced by Hermann Ebbinghaus, or the use of non-words that mimic the structure of real words in experiments in psycholinguistics.
An example of a vocable is "la la la".