This is a question that bothers me for a really long time. For example, Russians in every (not literally, but you get the point) Hollywood movies/TVshows are acted by English-speaking actors. It is really annoying to see the roles where “fluent” or “native” speaker twists a foreign language. It is embarrassing.
I'd like to know, is there any reason, why Hollywood does not use native speakers. I'll bet there are tons of different language speaker actors around LA, but still, in production, we hear ridiculous goo. And I don't whine about main roles, I can forgive Julia Roberts or George Clooney if they have a line or two in Mandarin. But, when there is a tiny part of the picture with 4 Armenian mobsters, why they could not be real Armenian actors, so it feels right in the details?
Is there any reason not to use native speaker actors?
I am from Estonia, it is a really small country (about 1.3 mln people), but even Estonian actors are available in LA, and I am pretty sure, they are not more expensive while more than good professionally for those small roles, which rarely pop up. So why Hollywood still use Serbians who never spoke Serbian?
Or Russians? There are hordes of them in LA, certainly. Why not pick them in Russian roles?
I admit, French, Italian and Spanish have much better coverage, but even German is frequently the rubbish.
Even when the writer is made a good job for background details it goes downhill (in this aspect) after casting...
There must be a rational reason for the situation. Maybe it's about trade unions?
Edit on starting bounty
I have read the answers below for some days now, and I must admit: I am not convinced. I think it is good to start a bounty to call more opinions to reveal more possibilities.
Most important, I state: for me, this question is about authenticity, I want to believe the story told on the screen. Bad use of language is a real turnoff, for me. Like there is a lot of people, who find disturbing when certain dialect of English is not accurate.
I analyze some hypotheses so far, to show, why I can't accept those as an Answer.
Reason 1: it is very hard to find foreigner actors in Hollywood
Hollywood is soon a century a place that sucks young actors around to globe into. For now, there should be them in any nation and any age, both men and women. Certainly not any combination of any, but still. There is no other place like this on Earth, to my knowledge.
Same time European small studios use most times native speakers in corresponding roles, whenever and as close as possible. As from @AryanSonwatikar comment, seems Bollywood acts the same way.
Reason 2: budget does not allow
Hollywood shows have budgets in the industry no comparable with anything else.
If we think a bit how much is contributed to visual integrity and right shooting places, for example, and how much things are developed in this area during 50-60 years, this is been all in the name of being more believable. Compared with all those expenses seems argumenting with a budget in native speaking actors topic somehow hard to grasp. Are they more expensive in small roles?
Would be filling small roles with unknown actors more expensive than using known actors as fake natives? Rather not, I think. Of course, unknown adds risks, so from this aspect there are downsides. Including rookies (or different work ethics or culture) has always its benefits and worries. Still, it seems more about the next reason:
Reason 3: being risk-averse
This seems so far most convincing. Still, it is risky to belittle your audience, too. Or?
Here belong also networking: using people who you already know or are in certain circles already. Use them, they have already proved themself...
Reason 4: actors box office value
Unless we talking about leading actors or supporting actors, this seems not relevant to me.
Reason 5: casting (and actually nobody) does not understand it anyway and can't tell how authentic it was (speaking some native language)
This is a tricky one. I want to apologize already for everyone who finds following somehow insulting. But this is really hard to understand to me.
I try to explain it from my perspective (it is certainly not one-to-one with everyone, but still I found it pretty common here, where I live). If I hear somewhere in the World some (not known to me) Estonian to speak whatever another language I almost always can point out that the speaker is Estonian. Takes years and years every day speaking to mask your mother tongue, to get it sound really fluent (depends also from the person and how close is language to yours). And, for some degree I can use the same method for some shortlist of other languages, I have more experience.
Now, following my own (but common here) experience it is hard to understand, how casting managers can't make a difference between being fluent or being English trying to fake? I understand that on casting is almost impossible to tell, does actor really speak Latvian or maybe Lithuanian, but for attentive listener should be not too hard to detect your mother tongue in the speaker's "native" language. Or?