The spelling of the word "Luthy" can be explained using the International Phonetic Alphabet (IPA). The first sound is /l/ which is a voiced alveolar lateral approximant. The second sound is /ʌ/ which is an open-mid back unrounded vowel. The third sound is /ð/ which is a voiced dental fricative. The fourth sound is /i/ which is a close front unrounded vowel. The final sound is /j/ which is a voiced palatal approximant. The correct spelling of this word is crucial in ensuring effective communication and proper pronunciation.