The spelling of the word "FOSLIR" can be explained using the International Phonetic Alphabet (IPA) transcription. The first syllable "FOS" is spelled with an /f/ sound, followed by an /ɒ/ vowel sound and an /s/ consonant sound. The second syllable "LIR" is spelled with an /l/ consonant sound, an /ɪ/ vowel sound, and an /r/ consonant sound. The combination of these sounds results in the unique spelling of the word "FOSLIR."