Sean Connery speaks several lines of Russian dialogue at the beginning of The Hunt for Red October, prior to switching to English.
Did Connery spend time learning Russian for this part, or did he simply memorize the phrases?
It seems unlikely that Connery would have had time to learn Russian as he was a last minute replacement.
The film had been under production for two weeks when word came that Klaus Maria Brandauer (Out of Africa), the Austrian actor who'd been signed to play the rogue Soviet sub commander Marko Ramius, couldn't do it after all because of a prior commitment. Connery took the part instead, needing only one day for rehearsal.
Linked within that reference is a link to an AP report by Bob Thomas in the Lawrence Journal of March 7th 1990 quoting Connery on "learning Russian" as
"It wasn't hard," he said [Connery]. "they were all one-liners"
It's been commented quite prevalently that Connery speaks Russian with a Scottish accent [not uncommon for Connery when dealing with accents..see Highlander.]
Unchecked Reddit comments elsewhere have said
...he didn't even bother pronouncing several of the words, much less saying them even remotely accurately. No Russian speaker would understand him without subtitles. In fact, when that movie came out in Russia, it was released with what's called voice-over translation, and typically anything that is clearly understood (or spoken in Russian) is left as is without translation (since you can hear all the original dialogue underneath the dubbing)... but not in the case of Sean Connery.