The YouTube app on Android and iPhone shows only one caption track at a time, so it cannot display two subtitle languages together. To watch with dual subtitles on a phone, you need an app that plays the YouTube video under its own subtitle layer. Trancy and Linglass do this for any YouTube link on both Android and iPhone, and Jolii does it on iPhone. If you are learning English or Japanese, LingoDew (which we make) does it for its own selection of videos, with every word tappable. You can also try LingoDew in a phone browser without installing anything. Desktop extensions like Language Reactor do not run in the YouTube app.
Facts below were checked on 25 October 2026 against Google’s YouTube Help pages and each app’s App Store and Google Play listing. We make LingoDew, so we only state what you can verify.
Your options at a glance
| Method | Two subtitle lines | Tap a word to look it up | Any YouTube video | Install needed | Cost |
|---|---|---|---|---|---|
| YouTube app captions | No, one at a time | No | Yes | No | Free |
| Trancy app | Yes | Yes | Yes | Yes (Android, iPhone) | Free download, paid Premium |
| Linglass app | Yes | Yes | Yes | Yes (Android, iPhone) | Free download |
| Jolii app | Yes | Yes | Yes, by link or your account | Yes (iPhone) | Free download, in-app purchases |
| Migaku app | Clickable target-language subtitles | Yes | YouTube | Yes (Android, iPhone) | Paid subscription, from US$10/month |
| LingoDew app | Subtitle plus translation line | Yes, aligned to the spoken word | No, LingoDew’s selection of English and Japanese videos | Yes (Android, iPhone) | Free to start; Pro US$4.99/month |
| lingodew.com in a phone browser | Subtitle plus translation | Yes | No, same selection | No | Free |
Option 1: the YouTube app (one language at a time)
The YouTube app is fine if one subtitle line is enough. Google’s help pages describe the steps:
- Open the video and tap the player once to show the controls.
- Tap the Closed captions (CC) icon to turn captions on. If there is no icon, the video has no captions.
- To change the language, open the player Settings and choose Captions, then pick from the tracks the video offers.
This gives you one language at a time and no word lookups. For language learning, the usual workaround is to watch once with captions in the language you are learning and replay the hard parts with captions in your own language. That works, but it is slow.
Option 2: a dual-subtitle player app (any YouTube video)
These apps open a YouTube video inside their own player and draw two subtitle lines, the original and a translation, that you can tap:
- Trancy (Android and iPhone): its App Store listing describes side-by-side bilingual subtitles for any YouTube video or podcast, AI-generated subtitles for videos without captions, and tap-to-translate.
- Linglass (Android and iPhone): its listing describes dual subtitles on any YouTube video, context-aware translation when you tap a word, and spaced-repetition flashcards for saved words.
- Jolii (iPhone): its listing describes dual subtitles for YouTube links and for your own YouTube or Netflix account, with tap-to-translate.
The usual flow: install the app, paste or share a YouTube link into it (or search inside it), choose the language you are learning and your own language, and play. If a video has no captions in the language you are learning, Trancy says it can generate them with AI. Machine-made subtitles can be wrong, so double-check lines that look odd.
Option 3: an app with its own video selection (English and Japanese)
Translating any video gets you two lines, but it does not tell you whether the video suits your level. LingoDew takes a different approach. It plays its own daily selection of English and Japanese YouTube videos and labels each one A1–C2 (CEFR) or N5–N1 (JLPT). Under each subtitle line you can show a translation; turn it off when you want to test your listening. Every subtitle word is aligned to the audio, so tapping a word opens its dictionary card (with furigana and romaji for Japanese) and jumps to the moment it is spoken. Saved words keep their sentence and come back for review on an FSRS schedule.
LingoDew does not open your own YouTube links, and it teaches only English and Japanese. Every video plays free without an account. The tap-and-save tools come free with today’s picks and recent videos, and Pro (US$4.99/month) unlocks them for the whole library.
Without installing anything
Every video on lingodew.com has its own page with the same time-synced subtitles, translations and word cards, and those pages work in a phone browser. Start from a level, for example JLPT N5 Japanese videos or CEFR A2 English videos, open a video, and tap any word in the subtitles.
Which option to choose
- Any video, two lines, on Android or iPhone: Trancy or Linglass.
- Netflix as well as YouTube on iPhone: Jolii.
- Learning English or Japanese and want videos at your level: LingoDew, in the app or in the browser.
- One language is enough: the YouTube app’s own captions.
On a laptop, desktop browser extensions add dual subtitles directly on youtube.com. If you are deciding between the two setups, see Language Reactor alternatives on Android and iPhone.