Firefox Brings CJK Translation to Android with Local Privacy

Mozilla has rolled out a major Firefox update for Android, bringing local translation support for Chinese, Japanese, and Korean (CJK) users. The move follows high demand on Mozilla Connect, where users had repeatedly requested better CJK coverage.

Unlike other browsers that process text in the cloud, Firefox handles translation entirely on the device. This means stronger privacy, faster results, and even offline use once the language models are downloaded.

“Firefox automatically downloads the model once,” explained Mozilla engineer Erik Nordin. “After that, translations happen on your phone. The content never leaves your device, and Firefox does not track what you translate.”

Mozilla notes that building translation for CJK wasn’t that easy. These languages rely on complex characters and lack spaces between words, making text segmentation difficult. Mozilla’s team had to overhaul algorithms and design lightweight machine learning models that still run smoothly on mobile hardware.

Firefox only translates the visible section of a page instead of processing everything at once to optimize performance. This makes the experience more responsive, especially on older or budget devices.

Mozilla relied on community testers fluent in Chinese, Japanese, or Korean to refine accuracy. Testers spotted real-world quirks, like one early model translating “stuffed mushrooms” as a plush toy. Their feedback helped fine-tune the final release.

CJK support has already doubled Firefox’s active translation users in Asia since landing on desktop. With Android support now live, even more users can browse the web in their own language, safely and privately.

You can try it by updating Firefox on Android or desktop, tap the translate icon on a CJK page, and the browser will handle the rest locally. In a related news, Firefox is soon getting built-in Google Lens support for image searches.