The correct spelling of the phrase "am favorite" is actually "I'm favorite". The contraction "I'm" is short for "I am". The word "favorite" is spelled with the letter "U" in British English, but is spelled with the letter "O" in American English. In IPA phonetic transcription, "I'm" is pronounced as /aɪm/ and "favorite" is pronounced as /ˈfeɪvərɪt/ in American English or /ˈfeɪvərɪt/ in British English.