Celyn

What is Celyn?

Celyn is a macOS app that provides real-time translation shown as subtitles “in your notch.” The core purpose is to help you understand spoken words during conversations and media playback without cluttering your screen.

It performs translation on-device so the audio input is processed locally on your Mac, and the app is designed to work with a simple start/stop hotkey rather than multiple windows or settings.

Key Features

• Real-time subtitles in your notch: Translation appears where your eyes already are, avoiding extra windows or screen clutter.
• On-device processing (private by design): Uses Apple’s built-in speech and translation frameworks with everything processed locally on your Mac.
• Offline support: Translation can run without internet access, with no API keys and no accounts to create.
• Hotkey controls: Press ⌥T to start translating and press again to stop.
• Language support: Supports 19 languages, including English, Portuguese, Spanish, French, German, Japanese, and Korean (with additional languages also supported).
• Audio capture options: Translation can use mic input, system audio, or both for different listening scenarios.

How to Use Celyn

1. Download and install Celyn for macOS (requires macOS 15 Sequoia or later).
2. Open the app and begin a translation session using the ⌥T hotkey.
3. Choose the audio source you need (e.g., mic, system audio, or both) depending on whether you’re translating a person, a call, or media.
4. View the translated subtitles in your notch while speaking or listening.
5. Press ⌥T again to stop the session.

Use Cases

• Zoom calls: Use mic and/or system audio capture to translate what’s being said during a live call.
• Watching YouTube or listening to podcasts: Translate spoken content from your Mac’s system audio while you watch or listen.
• In-person conversations: Start translation with the microphone to understand speech in real time.
• Multilingual media comprehension: Turn on translation while viewing or listening to content when you need instant understanding without switching apps.
• Working offline: Use Celyn in situations without internet access where you still want real-time translation.

FAQ

Is Celyn available for macOS only? Yes. The page states Celyn is for macOS and requires macOS 15 Sequoia or later.

Does Celyn require an internet connection? No. It states offline use is supported and that no internet is needed.

Does Celyn require an API key or an account? No. The page says no API keys are required and there’s no accounts to create.

What audio does Celyn translate? It supports mic input, system audio, or both, depending on the scenario.

How do I start and stop translation? Use the hotkey ⌥T to start translating, and press ⌥T again to stop.

Alternatives

• Browser-based live captions/translation tools: Useful when you primarily need translation inside a specific browser context, but they typically don’t provide the same always-on, notch-based subtitle workflow.
• Screen-reader or accessibility transcription tools: Can help capture spoken language, though translation and real-time subtitle placement may be less streamlined than Celyn’s notch display.
• Standalone subtitle or caption workflows: Some tools focus on translating or generating captions for media playback; these may be better for post-processing or file-based workflows rather than live, on-device translation.
• Other on-device speech-to-text + translation setups: General approaches that combine local speech recognition and translation may offer similar offline goals, but often require more configuration than a dedicated hotkey-driven subtitle app.