The spelling of the word "hyo" can be explained using the International Phonetic Alphabet (IPA) transcription. The word "hyo" is pronounced as /haɪoʊ/ with three distinct phonemes. The first sound, /h/, is an unvoiced glottal fricative. The second sound, /aɪ/, is a diphthong pronounced as "ahy," and the final sound, /oʊ/, is a dipthong pronounced as "oh." The spelling of "hyo" accurately reflects its unique phonetic elements, demonstrating the importance of IPA in understanding pronunciation and spelling.