Vocable is a noun that refers to a single syllable that carries a meaning despite not being a ‘real’ word. 

The Latin word vocabulum ( vo COB oo loom) has given us such English words as ‘vocal’ and ‘vocabulary.’ Our word of the day has been around since the Middle English period. Here’s an example:

When my kids are enjoying a meal, they tend to express it in the most vocable terms. They don't use actual words to convey their joy, just a simple, ‘mmmmm.’