The spelling of the word "AIRSAMSU" can be explained using the International Phonetic Alphabet (IPA) phonetic transcription. The first sound is the vowel sound /ɛ/, followed by the consonant /r/. Then, there is the vowel sound /sæ/ before the consonant sound /m/. The next two sounds are the vowel sound /u:/ and the consonant sound /s/. Finally, there is the vowel sound /ʌ/, completing the pronunciation of the word "AIRSAMSU."