But translation doesn't really work like that. There are significant tradeoffs between verbosity, cadence, meaning and subtext when translating. The different contraints are why the forieng dubbibg and foreign subtitles are usually quite different.
You generally only see word for word matches with subtitles when the subtitles are in the same language as the original lines spoken by the actors.
And the GP's example is the perfect illustration. "A murderer is Joe" sounds really weird. No native English speaker would ever say that. They would say, "Joe is a murderer" or "The murderer is Joe" or even "One of the murderers is Joe." But never "A murderer is Joe." Maybe in a Victorian novel, but not in a movie.
There are certainly tradeoffs, which is why I said I’d like the option.
Since I’m moderately familiar with the other language, I really just need the translation for words I don’t understand or mis-hear.
There is such a thing as a real-time translation. I’ve heard it in news broadcasts when a politician speaks a foreign language. It also happens all the time at the UN and other international negotiations. It works well but has downsides such as occasional latency while the translator needs to hear a few more words before they can translate.
It's a browser plugin that provides advanced subtitle functionality. You can have dusl sets of subtitles up, or just the original language subtitles with the option to pause and mouse over individual words for the definition.
You generally only see word for word matches with subtitles when the subtitles are in the same language as the original lines spoken by the actors.