The yellow cartoon canary called Sweety has a bizarre speech impediment that makes him pronounce the letter S as T; and this is why he's referred to as Tweety. He is also known as Tweety Pie – probably because this was the title of the first cartoon film that Sylvester the cat appeared in. Wikipedia clearly regards this as wrong, even though it states that in the 1951 single I Taut I Taw a Puddy–Tat, Mel Blanc sings (as Sylvester), "I'd like to eat that Sweetie Pie when he leaves his cage."
The character that would become Tweety was created by the animator Bob Clampett, and first appeared in 1942, in a cartoon film entitled A Tale of Two Kitties. The two kitties were named Babbit and Catstello – no prizes for guessing where those names came from. The Tweety prototype was a baby bird, of unspecified species, in a nest – named, according to Wikipedia, on the "model sheet" (whatever that is) as Orson. (This was also the name of a bird character from an earlier Clampett cartoon, released earlier in 1942 and entitled Wacky Blackout.) It was in his third appearance, in Birdy and the Beast (1944) that the bird was named Tweety.
The Black and white, lisping cat that would become Sylvester was created by Friz Freleng (best known for the Pink Panther) and first appeared in 1945. Bob Clampett left Warner Bros. in the same year, and Tweety was 'adopted' by Freleng, who first paired him with Sylvester in Tweety Pie (1947). This won Warner Bros. its first Oscar for Best Short Subject (Cartoons). It was presumably at this point that Tweety became Tweety Pie (to everyone except Wikipedia).
Tweety appeared in 46 cartoons between 1942 and 1962, and he also made a cameo appearance in Who Framed Roger Rabbit (1988). Sylvester, who was often paired with other characters such as Speedy Gonzales and Porky Pig, appeared in more than twice as many – 103 altogether (according to Wikipedia).
© Haydn Thompson 2022