The spelling of "McNellis" may seem tricky, but can be easily explained using the International Phonetic Alphabet (IPA). The first syllable "Mc" is pronounced as /mæk/, with the "c" representing the velar stop sound /k/. The second syllable "Nellis" is pronounced as /ˈnɛlɪs/, with the stress on the first syllable and the "ll" representing the lateral approximant sound /l/. When put together, the word is pronounced as /mækˈnɛlɪs/.
The word "McNellis" is a surname of Irish origin. It is derived from the Irish Gaelic name "Mac Néillíos".
The prefix "Mac" means "son of" in Gaelic, indicating a patronymic surname, while "Néillíos" is a given name. The given name itself comes from the Old Irish "Niall", which means "champion" or "cloud".
So, the etymology of "McNellis" suggests that it originated as a patronymic surname, meaning "son of Néillíos", which can be traced back to the Old Irish name "Niall", signifying a champion or a cloud.