There are a few words in the English language in which the letter combination GH is pronounced as F.
These include rough, tough, enough, and Julianne Hough.
Given how rare such words are, I thought that I knew them all, and was surprised in the last few days to learn a “new” word in which this linguistic oddity occurs: chough.
The name chough is applied to two Eurasian bird species in the family Corvidae; they are generally crow-like in appearance, but have orange or yellow beaks. The name is also applied to an Australian bird in a different family, Corcoracidae.
Therefore this example of a linguistic rarity is entirely unknown to English speakers in North America, but (presumably) well-known to English speakers in the British Isles and Australia.
Incidentally, this GH-as-F phenomenon reminds me of something that happened to me in second grade: I was reading one of the later books in the Wizard of Oz series. I understood every word in the book, except one: laughter. I thought that it was pronounced “lawter” (which would rhyme with slaughter, although I’m not sure if I knew that word either). For the entire book, I couldn’t figure out what “lawter” was, but I was able to deduce from the context that “lawter” occurred in mirthful situations.