The spelling of the word "rudnick" can be explained using the International Phonetic Alphabet (IPA). The first letter "r" is pronounced as /ɹ/, and the following "u" is pronounced as /ʌ/. The "d" is pronounced as /d/ and the "n" as /n/. Lastly, the "i" is pronounced as /i/ and the "ck" as /k/. Therefore, the IPA transcription of "rudnick" is /ˈɹʌdnɪk/. It is important to use phonetic transcription to ensure accurate pronunciation of words.