The spelling of the word "penitential of cummean" can be explained using the International Phonetic Alphabet (IPA). The first syllable is pronounced like "pen" /pɛn/, while the second syllable is pronounced like "i" /ɪ/ and the third syllable is pronounced like "ten" /tɛn/. The word "of" is pronounced like "ov" /ʌv/ and the final syllable "cummean" is pronounced like "koo-man" /kumen/. This phrase refers to a book of penitential codes authored by Saint Cummean, an Irish monk who lived during the seventh century.