The verb 'titter' emerged in English in the early 17th century, directly imitating the sound of a short, half-suppressed laugh. It is part of a rich tradition of onomatopoeic words for laughter, such as 'giggle' and 'chuckle', each capturing a distinct vocal quality. The word's formation relies not on the combination of classical morphemes but on the direct phonetic mimicry of a specific human sound. This sound symbolism provides the clear and intuitive link between the word's form and its modern meaning of a nervous or silly, restrained laugh.

The word 'titter' is considered a simplex word. It is an onomatopoeic formation, imitative of the sound of restrained or suppressed laughter.