Chatot is the only Pokémon that can naturally learn the move Chatter. Introduced in Pokémon Diamond and Pearl, Chatot is a Normal- and Flying-type Pokémon based on a musical songbird, with a colorful note-shaped pattern on its chest and a music-note-like crest on its head.
Chatter is Chatot’s signature move. In the Generation IV games, it is a Flying-type special attack that can confuse the target, and its distinctive feature is the Nintendo DS microphone: players could record a sound for Chatot’s cry, which affected the move’s in-game audio. Later games changed or removed some of those recording functions, but Chatter remained strongly associated with Chatot.
Smeargle is the usual source of confusion because its move Sketch can copy many moves used by opponents. However, Sketch cannot be used to learn Chatter, so Chatot remains the canonical answer. Chatter was also one of the moves tied to Chatot’s availability and learnset in the Sinnoh-era games, helping make this bird Pokémon unusually memorable despite its relatively narrow role.