The short answer: subtitles in the language you're learning teach you more, once you can follow them. Before that point, subtitles in your own language keep you watching but teach you little. The best option for most learners sits in between, and you should move along that line as your level grows.
Here's the research behind that answer, and a practical way to choose each evening.
The four options, compared
| Subtitles | How much you understand | How much you learn | Main risk |
|---|---|---|---|
| Your language (L1) | High | Low | You read the story and ignore the audio |
| Learning language (L2 captions) | Low to medium | High, if you can follow | Too hard: you decode text instead of watching |
| Both at once (dual) | High | Medium | You read the easier line |
| None | Depends on level | High for advanced learners | Frustration, giving up |
Why target-language subtitles win (when you can handle them)
A meta-analysis covering 30 years of captioning research found large benefits from watching with captions in the target language, compared with no captions: for listening comprehension (g = 0.99) and vocabulary learning (g = 0.87) (Montero Perez, Van Den Noortgate & Desmet, 2013). Those are large effects by education-research standards.
The reason: seeing a word while you hear it links its written form to its sound, and makes the stream of speech easier to split into separate words.
Why they fail for beginners
There's a threshold. To follow TV dialogue with some help, you need roughly 3,000 of the most frequent word families, which covers about 95% of what's said (Webb & Rodgers, 2009). Following spoken language with no help at all takes an estimated 6,000–7,000 (Nation, 2006).
Below that threshold, target-language subtitles don't feel like immersion. They feel like a reading test on a timer. Most people switch back to their own language within ten minutes, and the episode teaches them nothing.
What about both at once?
Dual subtitles look like the perfect compromise, and they do help comprehension. But eye-tracking shows where attention goes: with bilingual subtitles, learners spend more time reading the translation than the target words, and only attention to the target words predicts learning (Wang & Pellicer-Sánchez, 2022). Given two lines, you read the easy one.
Dual is excellent for studying a specific scene. It's a weak default for a whole series. More on this in our guide to dual subtitles on Stremio.
The option most people never try: mixed subtitles
There's a fifth option that doesn't appear in most guides: your own language, with a few learning-language words in place.
This isn't a gimmick. Researchers have built systems that generate this kind of mixed-language text for vocabulary learning (Labutov & Lipson, 2014). The idea is that a viewer who never loses the thread keeps absorbing, while one who stalls stops. And a study comparing subtitle sequences found that starting with L1 subtitles and then moving to bilingual ones gave the best word recall and the lowest cognitive load (Yuan, 2025).
Two ways to go further:
- Mostly your language, a few new words. Comprehension stays intact, and the new words arrive in context. (BingeLingo calls this Bridge.)
- Mostly the learning language, your language only where a line would lose you. Harder, and more learning per minute. (BingeLingo calls this Immersion.)
How to choose, by level
- Beginner (A1–A2): your own language with a few new words mixed in. Don't force target-language captions yet; you'll quit.
- Lower intermediate (A2–B1): mixed subtitles most evenings. Try target-language captions on a show you've already seen.
- Intermediate (B1–B2): target-language subtitles, with help only on the lines that would stop you.
- Advanced (B2+): target-language captions, then no subtitles on shows with clear dialogue.
A useful gut check: if you're reading more than you're watching, step down one level. If you rarely look at the subtitles, step up.
Whatever you choose, watching isn't enough
Every option above improves what you take in. None of them makes you remember. Recognising a word on screen and recalling it later are different skills, and repeated self-testing beats re-exposure on delayed tests, 61% versus 40% in the classic study (Roediger & Karpicke, 2006).
So, after an episode, spend three minutes testing yourself on the words that came up. BingeLingo does this automatically with a 12-question recap after each title, then brings words back on a spaced schedule.
The full research write-up is here. If you watch in Stremio, you can try all three subtitle modes free.