Subline Download

A Mac app for language learners

Learn languages with YouTube.

Paste a video link and Subline shows the video next to a clean transcript, laid out as a dialogue. The transcript follows the audio word by word, and you can save vocabulary as you watch.

Download for Mac Apple silicon Download for Mac Intel

Free for 7 days, no account or card · macOS 13 or later · Which one is my Mac?

Study the videos you actually enjoy

Street interviews, podcasts, cooking shows: if it is on YouTube, it becomes a lesson you can replay sentence by sentence.

  • Dialogue transcript

    Sentences are punctuated, grouped by speaker and named when possible, with an optional translation line in your language.

  • Follows the video

    The current sentence and word are highlighted. Click a sentence to replay it, loop it, or pause after each sentence for shadowing practice.

  • Folders

    Nest folders to any depth (🇪🇸 Spanish › Street interviews › Daily life), give them an emoji, and drag and drop folders and videos.

  • Vocabulary

    Select words to save them with their sentence and timestamp, then export them to CSV, ready for Anki.

  • Claude formats the text

    Raw captions become a readable dialogue, in the speakers' own words. Use your Claude app with no API key, or your Anthropic API key.

  • All local

    Everything is stored as plain files in a folder you control. Export everything writes your transcripts (Markdown) and vocabulary (CSV) to a folder in one click.

Made for the keyboard

Space
Play / pause
← →
Previous / next sentence
R
Repeat the sentence
L
Loop the sentence
P
Pause after each sentence
[ ]
Slower / faster
T
Show / hide the translation
⌘K
Open any video or folder

From a link to a lesson in a minute

  1. Paste a YouTube link

    Pick human captions for the most accurate text or auto-generated ones for exact word timings, or attach your own .srt or .vtt file. A basic transcript is ready in seconds.

  2. Let Claude format it

    Claude adds punctuation, splits sentences, names the speakers and can add a translation line. It only fixes obvious recognition errors and keeps what people actually said.

  3. Watch, repeat, save words

    Click any sentence to play from there, loop the hard parts, slow down, and select words to add them to your vocabulary.

Free for 7 days. No account, no card.

Download Subline and use all of it for a week. The trial runs on your Mac and never goes online. If you like it, buy a license once to keep using it.

Subline license

One-time purchase

  • Use it on up to 3 Macs.
  • Paste the key from your purchase email into Settings › License.
  • New Mac? Deactivate the old one in the app or from your purchases page.
  • Your library is always yours: Export my data works even after the trial.
Buy Subline

Payment and receipts are handled by Polar, the Subline store.

Your data stays on your Mac

Everything lives in one folder you choose, as plain JSON files. There is no Subline account.

  • Back it up by copying the folder.
  • Put it in iCloud Drive to share it between Macs, one Mac at a time.
  • Your Anthropic API key never leaves the macOS Keychain.

Nothing is sent anywhere except

YouTube
for video details, captions and playback.
Anthropic
only when you format a video with your API key.
Your Claude app
when you ask it to format a video.
Polar
when you activate your license and about once a day after that: your license key, your Mac's name and a one-way hash of its hardware id. The trial itself never goes online.

Get Subline

For Apple silicon and Intel Macs with macOS 13 or later.

  1. Install yt-dlp

    The open-source tool Subline uses to read YouTube captions. With Homebrew: 

    brew install yt-dlp

  2. Download Subline

    Open the disk image and drag Subline to Applications.

    Download for Apple silicon Download for Intel

Which one is my Mac? Open the Apple menu › About This Mac. If it lists a Chip such as Apple M1 or later, choose Apple silicon. If it lists an Intel Processor, choose Intel.

First launch: Subline isn't notarized by Apple yet, so macOS says it can't verify the app. Click Done, then open System Settings › Privacy & Security and click Open Anyway next to Subline. You do this once per version.

Subline tells you when a new version is out. Download it and drag it to Applications to replace the old one: your library, settings and license stay.