Here's a breakdown:
* Phoneme: A basic unit of sound that distinguishes one word from another. For example, the sounds /k/ and /t/ are phonemes in English because they differentiate words like "cat" and "tat".
* Phone: An actual speech sound produced by a speaker. These sounds can vary slightly depending on context and speaker.
* Allophone: A variation of a phoneme. For example, the /p/ sound in "pin" and "spin" are allophones of the same phoneme, but they are pronounced differently.
While phonemes are considered the smallest units of *meaningful* sound, there are even smaller units called features. These are the individual acoustic properties of a sound, like voicing (whether the vocal cords vibrate), place of articulation (where in the mouth the sound is produced), and manner of articulation (how the air is manipulated).
So, to sum it up:
* Phonemes are the smallest units that change the meaning of a word.
* Phones are the actual sounds we produce.
* Allophones are variations of phonemes.
* Features are the building blocks of phonemes.