When you can speak multiple languages or dialects and switch back and forth between them in order to make a point, that’s called code-switching. When you speak a single language or dialect and employ the forms of a different one for no clear reason, that’s called affectation. As always there are boundary cases.
The French pronounce this [ˈkwɔsɔn]. Most Americas say [kɹ̩ˈsɑnt]. Croissant is a loan word, but we’ve been eating croissants over here in North America for long enough that I think we can call this a fully-fledged member of the English lexicon, recognizably French spelling notwithstanding. However, it’s not uncommon for me to hear (presumably monolingual) English speakers say [ˈkwɔsɔn] to other (presumably monolingual) English speakers in an otherwise English-only context. This sounds affected to my ears, but whenever I’ve heard it the usage has been so unselfconscious–so devoid of wince-inducing social jockeying–that I wonder if there is an actual lexical change afoot.
New Orleans, Long Island, Shanghai
Here’s something that I do so I don’t think it’s affected, but you be the judge. When saying the names of places I’ll lean towards a well-known native pronunciation instead of what would be standard for my dialect. So given a choice between [nju ɔɹˈlinz], [nju ˈɔɹlɪnz], or [ˈnɔlɪnz] (N’awlins for you non-linguists) I’ll opt for the last one, even though the total amount of time I’ve spent in New Orleans is about two days when I was five. Likewise I say [lɔnˈgaɪln̩d] instead of [lɔŋ aɪlæn̩d], hitting that medial /g/ hard like a loanshark does a deadbeat. More subtly for an American, I pronounce the name of the China’s largest city [ʃɒŋhaɪ] instead of [ʃæŋhaɪ] because that’s how I’ve heard Chinese people say it. (Though I say [ʃæŋhaɪ] for the verb that means to kidnap someone and force them to serve in your navy, because that’s a different lexical item. I also refer to the 1986 Madonna/Sean Penn vehicle as [ʃæŋhaɪ supraɪz], but perhaps it is best if we don’t speak of this at all.)
There’s a limit of course. I’m not going to say “Last summer I took a lovely vacation in [mɛxiko]” because I don’t want to sound like a schmuck. I suggest the native pronunciation without trying to sound convincingly native myself. What this translates to into phonetic terms is borrowing segments and broad stress patterns, but drawing the subtler aspects of pronunciation (e.g. vowel quality) from my own dialect.
All these issues come together in a crucial aspect of Wittgenstein scholarship: how should an English speaker say his name? As I see it, there are four options.
- [wɪtgɪnstaɪn]…This is reasonable because it is consistently anglicized in a here-in-America-we-speak-American-buddy kind of way.
- [vɪtgɪnstaɪn]…This is how I say it. It’s pretty standard and sounds reasonable, but when you think about it, just changing the initial consonant while leaving everything else the same is kind of sloppy. This pronunciation belongs to a dialect that I call War Movie German, which is identical to English except for the addition of the lexical items “achtung” and “jawohl” and the single phonetic rule #w → v.
- [vɪtgɪnʃtaɪn]…Logically this seems better than (2). If you’re going to try and sound German you might as well go all the way, but to my ears something is off. I think because the segment change v→w is so much more famous as a German stereotype than s→ʃ that the latter perversely comes off affected by comparison.
- [wɪtgɪnʃtaɪn]…See sounding like a schmuck above.