The spelling of the word "CAFAU" can be explained using IPA phonetic transcription. This word is pronounced as "kæfaʊ" with the first syllable being pronounced as "kæ" with a short "a" sound and the second syllable "faʊ" having "au" sound which is diphthong with both "a" and "u" sounds. Therefore, the spelling of "CAFAU" is a phonetic way of representing the pronunciation of the word. It is important to understand IPA for better communication and to avoid mispronunciation of words.