The spelling of the word "Hoonoomaun" can be explained using the International Phonetic Alphabet (IPA). The word can be broken down into individual phonemes, which are the smallest units of sound in a language. The first sound in "Hoonoomaun" is /hu/, which is a voiced back rounded vowel. The second sound is /nu:/, which is a voiced alveolar nasal. The third sound is /mɔn/, which is a voiced bilabial nasal. Putting these sounds together gives us the word "Hoonoomaun."