What is the smallest unit of sound in linguistics?

What is the smallest unit of sound in linguistics?

Explanation

A phoneme is the smallest unit of sound in a language 

The smallest unit of sound in speech that makes a difference in communication.

For example, the sounds "p" and "b" are different phonemes, as they differentiate the words "pat" and "bat". 

Sound Units: A Summary Sound units of spoken language, from largest to smallest, include
  • Syllables
  • Onsets 
  • Rimes
  • Phonemes