The spelling of the word "BAE PAI" can be explained using the International Phonetic Alphabet (IPA). "Bae" is pronounced as /beɪ/ where the "ae" combination makes a long vowel sound similar to "ay". "Pai" is pronounced as /paɪ/ where "ai" make another long vowel sound. Together "BAE PAI" is pronounced as /beɪ paɪ/. It is important to use phonetic transcriptions to accurately represent the sounds of spoken words, especially when dealing with words from different languages or dialects.