How to Change the Language in Mozilla Firefox

If you use a computer with a different default language from the one you are most comfortable with, or if you simply prefer to navigate your browser’s menus, settings pages, and error messages in a specific language, Mozilla Firefox makes it easy to change the browser’s display language. Beyond the browser interface itself, you can also set your preferred languages for websites, telling multilingual sites which language version to serve you first.

The Difference Between Browser Language and Website Language

It is useful to understand that Firefox manages two related but separate language settings:

• Browser Language: This controls the language used for Firefox’s own interface — the text in the Settings menus, toolbar tooltips, error messages, and dialog boxes.
• Website Language Preference: This sends a ranked list of your preferred languages to every website you visit via the HTTP “Accept-Language” header. Websites that support multiple languages will use this list to decide which version to show you automatically.

You configure both of these independently within Firefox’s Settings menu.

How to Change the Browser Interface Language

1. Open Mozilla Firefox on your computer.
2. Click the Menu button (the three horizontal lines icon, often called the hamburger menu) in the top-right corner of the browser window.
3. Select Settings (or “Preferences” on macOS).
4. Ensure you are on the General tab in the left-hand sidebar.
5. Scroll down to the Language section.
6. Find the dropdown menu labelled “Choose the languages used to display menus, messages, and notifications from Firefox.” Click it.
7. If the language you want is already listed in the dropdown, select it. If not, scroll down to the bottom of the list and click Search for more languages…
8. In the “Firefox Language Settings” popup window that appears, click the “Select a language to add…” dropdown, find and select your desired language, then click Add.
9. Click OK to close the language settings popup.
10. A Restart Firefox button will appear next to the language setting. Click it to restart the browser and apply the new language.

After restarting, Firefox’s entire interface will display in the language you selected.

How to Set Preferred Website Languages

Many websites are published in multiple languages. You can tell Firefox which language you prefer websites to display in, and even set up a priority order as a fallback.

1. Return to Settings > General.
2. Scroll to the Language section and look for the text “Choose your preferred language for displaying pages.”
3. Click the Choose… button to the right of this text.
4. A “Languages” dialog box will appear. Click the dropdown at the top labelled “Select a language to add…” and choose your primary preferred language. Click Add.
5. You can add multiple languages to build a priority list. Use the Move Up and Move Down buttons to rank them. For example, you could set Spanish as your first preference, and English as your second. If a website does not have a Spanish version, Firefox will automatically request the English version instead.
6. Click OK to save.

Troubleshooting: Website Still Showing Wrong Language

If a website is still displaying in the wrong language after you change Firefox’s settings, it is likely because the website detects your country from your IP address rather than reading the browser’s language preference. In this case, the solution is to look for the website’s own built-in language selector (often a globe icon or flag in the footer) and change your language preference directly within that website’s settings.