Actors who can't really speak the language.

[William Camden]

I'm sure this happens quite a bit, but some of them also actually learn the language. Viggo Mortensen, for example, actually did learn Arabic (and modified his existing but imperfect French) for "Far from Men".

I saw Mortensen in the Spanish film Alatriste (apparently he speaks fluent Spanish). He played the title role of a 17th century Spanish soldier. I didn't recognise him until the credits went up.

[Montmorency]

I have read that when she starred in "Day for Night" ("La Nuit américaine"), Jacqueline Bisset, who despite her French-sounding name was brought up as an English speaker in England, felt that her French wasn't really good enough, and had to really work hard on her lines. However, this didn't really matter at all because she was playing a version of herself, i.e. an English actress starring in a French film (the film within a film). I would guess that Truffaut actually played up to this and adapted the film accordingly. Indeed, we see her in her room at night learning the lines for the next day (which Truffaut, playing a version of himself, has only just written and delivered that evening).

(It could be of course that she was being over-modest about her abilities, since, according to Wikipedia, her mother ("of French and English descent"), taught her to speak French "fluently", and she also went to the Lycée Français Charles de Gaulle in London).

[Serpent]

Shekhtman describes an actor who found learning the islands easy and fun

[arthaey]

I couldn't even read it! So I asked my manager to tell Televisa I wanted $500,000 for 100 episodes, thinking they'd go away. But they came back and said ok. ... I made over $2 million doing that show."

If any TV execs are lurking on the forum, let it be known that I am not only willing to not speak your country's language yet, but ALSO willing to not know how to act yet, for a cool one million. Quite the bargain, I'd say!

[tarvos]

I'm sure this happens quite a bit, but some of them also actually learn the language. Viggo Mortensen, for example, actually did learn Arabic (and modified his existing but imperfect French) for "Far from Men".

I saw Mortensen in the Spanish film Alatriste (apparently he speaks fluent Spanish). He played the title role of a 17th century Spanish soldier. I didn't recognise him until the credits went up.

He speaks fluent Spanish yes, because he grew up in Argentina. But the man is quite the accomplished polyglot.

[aokoye]

Do actors, or for that matter, opera singers, actually learn languages, to some extent, by memorizing and performing dialog?

I've seen the soprano Jessye Norman say in an interview that that she will not perform an opera in a language that she hasn't learned and that there are a lot of Russian operas she'd love to perform but she doesn't know Russian (and I think she mentioned somewhere that she just doesn't have the time to learn it - which seems logical) and thus won't learn the parts. From an interview:

I want to be able to express, I want to be able to communicate, and I want to be able to understand what it is I'm doing, and I want the people whose language it is to understand what I'm doing. And to help me with that, I need to listen to people speaking their own language, to listen to the difference in nuance which, of course, is just... I just love languages, and I love learning and I love listening. I love being able to listen to Italian and to be able to tell that that person comes from north Italy, and that person is from southern Italy, and that person is from Napoli. Only people from Napoli speak Italian like that, and I enjoy that sort of thing.

.

While she doesn't speak Hebrew either, she apparently works closely with a rabbi when she needs to perform something in Hebrew which leads me to think that she gives herself greater latitude to languages in non operatic contexts.

[Jimjam]

My favourite example of this would definitely be in the tv show "Arrow". We are lead to believe that during the 5 years he was on the island, he became fluent in mandarin chinese and russian and possibly others(there were circumstances that lead to him learning the languages but spoilers). This was shown by him speaking mandarin to a chinese native who was blindfolded at the time and the man then said that the one who was interrogating him spoke perfect mandarin and must definitely have been a native speaker. He actually had one of the worst chinese accents I have heard and I took 1st year mandarin at university so I got to hear some pretty bad accents.
I have no idea about russian though so I can't comment on it.

Then there was Brian Cranstons japanese in godzilla. While it wasn't the worst accent i've heard, but it had a very strong "samurai" like quality.
I've never understood why they don't get some sort of vocal coach to help them at least fake a decent accent. Then again, only language nerds like us on this site actually care about this sort of thing.

[Ando Jururu]

Katrina Kaif works in Bollywood movie industry, yet she cannot speak Hindi.
She learns her lines by heart. She has never ever spoken Hindi in an interview
(no wonder, she is British!), yet, she's one of the greatest starts in India.
Her real name is Katrina Turquotte, by the way.

[LMAshton]

Katrina Kaif works in Bollywood movie industry, yet she cannot speak Hindi.
She learns her lines by heart. She has never ever spoken Hindi in an interview
(no wonder, she is British!), yet, she's one of the greatest starts in India.
Her real name is Katrina Turquotte, by the way.

Too funny! I was going to bring up Katrina Kaif. She's the poster girl for bad Hindi with a terrible accent.

There have been a few other Bollywood movies I've seen with characters speaking in terrible accents, terrible enough that I, a non speaker, can tell are bad. The husband (fluent in Hindi), confirms that yes, that was really atrocious. It's usually white actors playing a character who grew up in India.

[Chris]

Speaking generally, I'm always more impressed with a film that features foreign languages, plus the fact it's a good 'advert' for learning 2nd, 3rd languages.