Update, 4 October 2026: the Chrome extension is out. Here is what it does and how to start, free. The parts about the extension below now describe the version you can install.
If you learned your first Japanese words from a show, you already know the problem. The characters shout, they drop particles, they call each other things you should never call a stranger. And yet an episode is forty minutes of real pronunciation, real rhythm and real emotion, which no textbook can give you.
What the Chrome extension does with an episode
Prima listens along with the tab. Where Chrome can make Japanese subtitles on your computer, the lines appear over the video with the translation in your language under them. About every minute of speech, at the end of a line, she pauses the video, says the line (or a short piece of it) slowly and asks you to say it back; then she asks one easy question about the scene, in Japanese, and lets the episode continue. Unknown words go to your Review list. Some protected players give extensions no sound at all; the panel tells you when it cannot hear a tab.
The polite-or-casual problem
The extension does not label lines for you. What you can do in a practice moment is ask, in your own language: "is that casual?" Prima answers in a sentence or two, then goes back to the line. By the end of a season you will have a working sense of when desu belongs and when it makes you sound like a customer-service robot.
Lessons you can take today
The course already has a whole topic for this, Shows & anime, and it works in the web app now. "Recap the last episode" trains the past tense on something you care about. "Casual or polite?" puts you at a convention with an older fan you admire, and the lesson is about switching from polite to casual as the conversation warms up. At the advanced level, "Dub or sub?" is an argument about craft, not taste.
What it cannot do
It cannot make you a native speaker in a season, and it does not pretend to. It gives you a habit that fits around something you already do every week, with the cringe pointed out before it happens.