This tool allows you to see how a word is actually used in context. It requires you to have subtitle and video files (if you use MKV files it will extract the subtitles).
You can download most japanese anime subtitles from Kitsunekko

Please install VLC
This is super alpha release, please post your bugs here and i'll update it.

Download

Run in the exe inside the dist folder.

Library lets you add stuff. "Extract from MKV" option enables subtitle extracting when you import MKV files. It's off by default
1) Add some media. (Add dir -> Anime folder)
2) when its finished you should end up with a long list of every spoken sentence in all of the videos/subtitles you added.
3)You can search at the top for any word (or you can use regular expressions eg: 私は.*です)
3) you can select multiple results, and press play. It will then queue a list of 10 second clips into VLC.

Is there a source code?

yea of course, but i dont feel like releasing it just yet. spot a bug?

I updated the layout and added an option so it doesn't automatically extract subtitles from MKVs (since they are in English usually, and you don't care about English.)

Updated some other stuff. If it was crashing on startup that's because it need's VLC installed.

now supports srt, ass, ssa files :-)