The correct spelling of the phrase "on top world" uses the IPA phonetic transcription /ɒn tɒp wɜːld/. The first word is spelled with an "o" sound, while the second word has a long "o" sound. The third word is pronounced with a stressed "u" sound and an "l" sound at the end. The word "top" is spelled with a "t" sound and an "o" sound with a short "o" sound. Finally, the word "world" has a "w" sound, a long "u" sound, and an "l" sound at the end.