The spelling of the word "COMPU" can be explained through the International Phonetic Alphabet (IPA). The initial consonant cluster "C-O-M" represents the voiceless velar stop /k/ followed by the mid-central vowel /ʌ/. The following consonant "P" represents the voiceless bilabial plosive /p/. Finally, the vowel "U" represents the high back rounded vowel /u/. Together, the IPA transcription for "COMPU" is /ˈkʌmpu/. This spelling provides a precise representation of the sounds used to pronounce the word.