Jag-waar sounds irredeemably posh. Everyone I know, including some guys who build the things, call it a Jag-you-er. Jaques is almost always pronounced dhzack.
I’ve never heard a UK person pronounce Jacques as Jay kweeze unless they are talking about the pretentious Shakespeare character in As You Like It and there we can just blame Bill.
The etymology of “niger” is from a Berber word for river, it’s got nothing to do with the Latinate word for black.
“We are the knights who say Nee-zhair.”
If this were a video game this zombie would have killed me by now.
Amazing how some threads can’t be killed. 
ixnay’s zombie.
To expand on this, a ‘z’ is generally thought of as a voiced ‘s’, so since /ʒ/ is a voiced /ʃ/, as the latter is pretty universally (phonetically) spelled “sh”, the former is given by “zh”.
Regarding the proper way to refer to people from Niger, why is Nigeran (pronounced nee zhair un) not typically used? Using Nigerien seems a bit too much like referring to people from Nigeria.
What determines the use of the -ois vs the -ien ending in French?
I’m pretty sure it depends on the day of the week. Most French seems to depend upon that.
This page lists thirty-something suffixes, so days of the week will not cut it.
I can’t think of any placename ending in a consonant where the adjective is formed by simply adding “-an”. The majority of the “-an” and “-ian” adjectives relate to placenames that already end in “-a” or “-ia”, where you just add “n” (India, Tonga, Samoa, Africa, Bavaria, Jamaica, etc.) There are plenty that don’t fit that pattern (Kansan, Athenian, Peruvian, Belizean) but they still don’t simply bolt “-an” onto the end of a word. So “Niger” -> “Nigeran” wouldn’t sound natural to me.
For years (maybe even on this thread years ago 
) it’s been pointed out English’s status as de facto sorta world language has brought with it a movement to banish idiosyncratic English spellings and/or pronunciations of foreign place names, even though there isn’t much movement against them in other languages (for example as noted on a recent thread, the name of the South American country used to be written Columbia in English, not just poetic reference to the US, Columbia U etc which still is; but now only the Spanish spelling is accepted in English for the country; but in German it’s ‘Kolumbien’ and AFAIK nobody ‘corrects’ that to the Spanish spelling).
Same here with NAI-ger as a ‘mispronunciation’. It’s the English pronunciation, the BBC be damned (plenty of US media outlets have been hipply calling it Nuh-ZHAIR for years also). The process just hasn’t reached names like ‘Germany’, yet. In some Brit accents the ‘a’ in France comes up fairly similarly to the way the French say it, not in an American accent but likewise we aren’t corrected on that, yet.
“Salvadorans” maybe for people from “El Salvador”? That’s all I got, though.
Damn. It must be the day of the month.
Damned complicated language.
You can’t have a discussion of french pronunciation without this illuminating joke: “The name is we ZELL!!”
But that’s not usually the way it works. Paris is a French city but we don’t say Paree. All countries adapt names of foreign places to their own languages.
Paris, Arkansas uses the English Pronunciation.
In the US, the original pronunciation of coupe had died out before the 1950s. It’s still current in the UK though.
Actually, it’s almost always the way it works. Localized pronunciations are the exception, not the rule, and generally only for very commonly spoken places. That’s why we don’t pronounce Nice as “neese,” why Americans don’t pronounce the Scottish city as Eddinberg, and so on.
I swear I remember “coo-PAY” in the US in the 80s. I don’t have any memories before the 80s, at least, and no British friends until much later in life. Perhaps I’m conflating memories of a much later time to an earlier one, but I swear I remember coo-pay being sometimes used growing up.