The spelling of the word "mcduffy" can be explained by using IPA phonetic transcription. The word is pronounced /məkˈdʌfi/. The "mc" is a common prefix in Irish and Scottish surnames and is pronounced as "mək". The "duffy" part is pronounced as "dʌfi". The combination of these two parts creates the unique and distinctive spelling of the word "mcduffy". It is important to note that this spelling may vary based on regional dialects and pronunciations.