Well, with Star Trek, it was supposed to be the universal translator, I think, but it only worked unless they wanted it NOT to - e.g., episode of ST:TNG where Picard and alien are on planet together and have to learn each other's language. (And they had a few other instances where they discussed language situations, like when Picard had to say a certain thing a certain way and where the deaf guy's 3 telepathic interpreters were killed and Data had to learn sign language.)

And like pepper_field said, looping - ZOMGosh! that episode (2010) of SG1 where Sam's pronunciation of Aschen was changed...and then later in the episode (or maybe in 2001) someone else said it the way Amanda had originally pronounced it - is another peeve. I guess it's hard for them to recapture the moment of acting, especially when it's days, weeks or even months later. Some are better at it than others.