The spelling of the word "Nellum" can be explained with the use of IPA phonetic transcription. The first syllable is pronounced as "nɛl", with the middle vowel sound having a short e sound. The following syllable is pronounced as "əm", with the final consonant sound having a soft m. Overall, the word's spelling corresponds well with its sound, as the letters "Nell" match the pronunciation of "nɛl" and the letters "um" match the pronunciation of "əm". The correct spelling of a word can significantly impact its meaning and understanding.