The spelling of the word "Mammais" can be explained using the International Phonetic Alphabet (IPA) transcription. The first syllable, "mam", is pronounced with a short "a" sound as in "cat" (mæm). The second syllable, "mais", is pronounced with a long "i" sound as in "bike" (meɪs). Therefore, the correct spelling of this word is "Mammais", with two "m"s and two "a"s in the first syllable and an "i" before the "s" in the second syllable.