linguen_

Take your YouTube channel global.

Support

Getting started, answers to the most common questions, and a direct line to the person who built the app.

Need help now? Email linguen.support@gmail.com. I reply within 2 business days.

To speed things up, mention your macOS version, what you were doing when the problem appeared, and the exact error message if there was one.

What Linguen does

Linguen is a Mac app that takes the videos already published on your YouTube channel and handles their localization at scale: it transcribes the audio, lets you review the transcript, translates subtitles into up to 31 languages, generates titles, descriptions and thumbnails, and publishes everything back to YouTube.

It runs entirely on your Mac. There is no Linguen account and no server of ours in the middle: the app talks directly to YouTube and to the AI provider you choose, using your own keys.

Requirements

Disk space: set aside a few gigabytes. Transcription runs locally and the app downloads a speech recognition model once.

Set aside 15 to 20 minutes for initial setup. The Gemini key takes two minutes, but YouTube API access requires creating a Google Cloud project and generating your own credentials — five screens in Google's console, each of which the app opens for you at the right place.

You do this once. After that the app connects on its own. It is also what guarantees that the YouTube API quota is entirely yours, with no shared queue and nothing passing through servers of ours.

Getting started

  1. Create your Gemini key

    Go to Google AI Studio, sign in with your Google account and generate an API key. It takes a few minutes. Copy the key and paste it into Settings → API keys in Linguen.

  2. Create your YouTube API access

    This is the part that takes time, and you only do it once. The first time an action needs YouTube, Linguen opens an assistant with these five steps and a button that takes you straight to each Google screen:

    1. Create a project in Google Cloud.
    2. Enable the YouTube Data API v3.
    3. Configure the consent screen: app name, your email, and audience type “External”.
    4. Under Audience, click “Publish app” so the status reads “In production”. Do not skip this: without it, sign-in returns Error 403: access_denied and access expires every 7 days.
    5. Under Clients, create a client of type “Desktop app” and copy the Client ID and Client Secret.

    Paste both credentials into the assistant and continue. They are stored on your Mac.

  3. Authorize access to your channel

    The app opens your browser asking you to authorize the Google account that controls the channel. Three things that look alarming and are normal:

    • A red screen appears saying “Google hasn't verified this app”. That is expected — the app is yours, created in the previous step. Click the small “Advanced” link, then “Go to… (unsafe)”.
    • If your account has more than one channel, pick the right one: Linguen binds to the channel you choose, and switching means reconnecting.
    • The permission mentions viewing, editing and deleting videos and captions. That is exactly what lets the app publish your subtitles and titles.

  4. Sync your catalog

    The app imports your published videos and shows, for each one, what already exists in every language and what is missing.

  5. Transcribe, review, translate

    Transcription runs on your Mac at no API cost. Review the text in the editor — that review is what carries quality into every translation downstream — then translate into the languages you picked.

  6. Publish

    Linguen uploads the subtitles and the translated titles and descriptions to YouTube, and can schedule your video releases.

Frequently asked questions

What does it cost to use?
The app is free to download. Pulling your channel catalog, transcribing on your Mac and exporting subtitles are free forever. The features that spend AI or publish to your channel — translation, titles and descriptions, thumbnails, coherence analysis and uploading to YouTube — require a monthly subscription, with the first month as a free trial. The price is shown on the App Store and on the app's Subscription screen, because it varies by country.

That is separate from the AI cost itself: whatever the AI features consume is billed by the provider, straight to your own account, with your own key — Linguen neither brokers nor marks up that cost. Transcription has no API cost at all: it runs on your Mac.
Why do I have to create a Google Cloud project? Wasn't signing in enough?
No, and that is a deliberate design choice. Linguen uses the YouTube API with your account and your quota, not ours. In exchange for 15 minutes of setup you get the entire daily quota to yourself, with no queue shared with other users, and the guarantee that none of your credentials or videos pass through a server of ours — because no such server exists. The app opens each Google console screen at the right place and validates your credentials on the spot.
I saw “Google hasn't verified this app”. Is that safe?
Yes, and it is expected. The warning appears because the Google Cloud app is yours, created by you minutes earlier, and Google's verification is only required for apps serving more than 100 people. Click “Advanced”, then “Go to… (unsafe)”. You are authorizing your own project to reach your own channel.
Do I also need an OpenAI or Anthropic key?
No. A Gemini key alone covers transcribing, translating, generating titles, descriptions and thumbnails, and publishing. The other keys are optional and unlock alternative translation modes and coherence analysis with other models.
Where are my API keys stored?
In the app's local database, inside Linguen's data folder on your Mac. They are never sent to us — only to the provider they belong to, at the moment of the call. You can delete them at any time in Settings.
Does the app work offline?
Transcription, subtitle editing and browsing your catalog work offline. Translation, image generation and anything that talks to YouTube need a connection.
Which languages are available?
31 languages in the catalog, and any of them can be your channel's source language. You choose in Settings which ones stay active in your workflow.
YouTube refused an upload and mentioned quota.
The YouTube API has a daily per-project quota that resets at midnight Pacific time. Linguen shows the day's usage in the header. If you run out, wait for the reset or spread uploads across more days.
Google authorization stopped working after about a week.
Almost always this is a Google Cloud project left in testing mode. In that mode Google expires access every 7 days, without warning. The fix is permanent: open Audience in the console, click “Publish app”, and reconnect once more from Linguen. The banner that then says your app “needs verification” is harmless and can be ignored.
Authorization stopped for some other reason.
It also happens when access is revoked in your Google Account or the password changes. Reconnect from within the app; if it persists, email me.
How do I remove my data?
Deleting the app removes the program. To also erase the local database with your catalog, subtitles and keys, delete Linguen's data folder in your user Library — email me and I'll send the exact path.

Found a bug or have a suggestion?

Write to linguen.support@gmail.com. Bug reports with reproduction steps get priority, and feature requests are read one by one.