One of the problems confronting every Brit who settles in France is to accurately and reliably produce the sounds which enrich the French language but which do not exist in English. Most notorious are the nasal vowels, of course, but alongside them must be ranked in terms of awkwardness the sound "u".
Often we go through an unfortunate period where we manage to produce a pretty good and solid "u", but through feebleness of brain, it insinuates itself into places where the sound "ou" should be heard. Thus it is that you often hear people talk about "us" while actually saying the word for "naked" - nu sommes, for example. Thankfully one of these words, nous, is a personal pronoun, while the other, nu, is an adjective, so the simple grammatical structure of the sentences in which they occur will make it difficult to misconstrue the sense intended, whatever the sound produced.
Not so with the word for the neck, cou. The neck is a part of the body, and sadly for us francophone Brits, so is the word produced if the sound "u" is substituted for the sound "ou", albeit in quite a different area of the body, and, to complicate matters, the word becomes impolite.
So I am glad that it is not until now, when I trust myself pretty well to say the word properly, that I have to try to see a doctor today with a rather nasty boil on my neck.