Firefox Introduces Machine Translation for Selected Text Fragments

In the nightly builds of Firefox, which will form the basis for the Firefox 126 release on May 14, a new feature has been added that enables automated machine translation of selected text fragments on a page. Previously, only full-page translation was supported. This translation function can be accessed through the context menu that appears when you right-click on a selected block of text.

How to Enable Fragment Translation

To activate the translation of selected text fragments, a new setting called browser.translations.select.enable has been added in about:config. By default, this setting is disabled and must be enabled manually.

Expanded Language Support

Additionally, the nightly builds now support translation into Russian, Ukrainian, and Estonian. In stable builds, these languages can only be used as source languages for translation, not as target languages.

Local Translation Engine

Firefox uses its built-in translation system, which performs translations locally on the user’s device without relying on external cloud services. This system is based on the open-source Bergamot engine, which serves as a wrapper for the Marian machine translation framework. Marian utilizes recurrent neural networks (RNNs) and transformer-based language models to deliver high-quality translations.