The spelling of the word "more lethiferous" can be broken down with IPA phonetic transcription. The initial "m" sound is followed by the "aw" vowel sound. The "r" sound is then pronounced, followed by the "l" sound. The "e" vowel sound comes next, followed by the "th" consonant blend. The "ih" vowel sound is then pronounced, followed by the "f" sound and the "er" vowel sound. The final "uh" vowel sound completes the word's pronunciation.