Analogous to synonym, typonyms are words that sound and mean the same but are spelled differently due to typographical error.
"Friend", "comrade" and "buddy" are synonyms while "friend", "firend" and "friedn" are typonyms.
A writer- and reader-friendly way of capitalizing the already-capitalized word "I", in order to add emphasis.
Bob: Hm...they said it wasn't a good idea.
Jane: Well EYE say, let's do it.