The spelling of the word "ketterman" is straightforward when using the International Phonetic Alphabet (IPA). The word can be broken down into four sounds: /k/ as in "cat," /ɛ/ as in "met," /t/ as in "top," and /ər/ as in "father." When putting these sounds together, the correct spelling becomes clear: "ketterman." The IPA helps to accurately represent the sounds of a word and provides a universal system for pronunciation.