The spelling of the phrase "more bottom side up" can be explained using the International Phonetic Alphabet (IPA). The first word, "more," is pronounced as /mɔː(r)/, with a long vowel sound in the middle. The second word, "bottom," is pronounced as /ˈbɒtəm/, with a short vowel sound in the first syllable and a schwa sound in the second syllable. The last two words, "side up," are pronounced as /saɪd/ and /ʌp/ respectively, with both words having a short vowel sound.