Unfortunately not, at least not in a convenient way. All of RS2's mission data is bundled together in one big binary, so you'd have to either find a way to unpack it or hex edit the entire script (constrained by the Japanese line lengths), and I just don't have either of those in me.
Using something like Textractor to pull and live translate the text in another window should be enough to know what you're doing at least, though the story is pretty much mangled in the process.