The word "phisai" is spelled using the International Phonetic Alphabet as /faɪseɪ/. This word refers to a Thai word that means "to separate" or "to divide". The spelling of this word can be a little tricky for English speakers as it includes the use of the "ai" diphthong, which combines the sounds of "a" and "i". Additionally, the final "ai" sound may sound like "ay" to some speakers, which can lead to confusion in spelling.