The spelling of the phrase "wert master of" can be explained using the International Phonetic Alphabet (IPA). "Wert" is pronounced /wərt/, with the "w" making a voiced bilabial glide and the "ə" representing a schwa sound. "Master" is pronounced /ˈmæstər/, with the "a" making a short vowel sound and the "ər" making a syllabic consonant. "Of" is pronounced /ʌv/, with the "v" making a voiced labiodental fricative and the "ʌ" making a short vowel sound. Overall, the phonetic transcription highlights the complexity and diversity of English pronunciation.