Money plays a good part in the conversion process.
A company is hired to translate a foreign movie so domestic audiences can enjoy it. I could use all the money to hire top-of-the-line actors and actresses for voice overs, and on primo translators for excellent dialogue. But whats the point? People are probably going to see the movie if they really want to, so why waste the time and money on getting the best of the best when Okay is good enough? You still get paid, costs are low, and people who wanted to see the film got to see it.
Another problem is space. Some languages can say more in less words and syllables than others. There is often a need to remove any extraneous verbage so the main point can be brought across.
This, of course, does not go for everything. Some movies do get the best of the best, and we are better off for it. Films like "Crouching Tiger, Hidden Dragon" and "Amelie" had great teams of translators for the subbed versions of these movies. In contrast, though, watch any Jackie Chan movie that was made in Hong Kong and was translated to English ("Rumble In the Bronx", "Supercop", "Operation Condor", "Half a Loaf of Kung Fu"). After you watch it, find a person who saw and understood the film in the original format and language. Everything will be different. Those are some of the worst 1 to 1 translation in a movie.
