The word "deum" is typically spelled with four letters: D-E-U-M. The IPA phonetic transcription for this word is /ˈde.ʊm/. The letter "D" represents the voiced alveolar stop /d/, while "E" represents the short vowel sound /ɛ/. The letter "U" represents the vowel sound /ʊ/, and "M" represents the bilabial nasal sound /m/. Overall, this spelling accurately represents the sounds of the word "deum" in English.