How To Change Firefox Language
To change the language in Firefox, follow these steps:
Open Firefox and click on the menu button in the top right corner (it looks like three horizontal lines).
Click on "Options" in the menu.
In the "General" tab, scroll down to the "Language and Appearance" section.
Under "Language," click on the "Choose" button.
In the "Language" window, select the language you want to use from the drop-down menu.
Click on the "OK" button to save your changes.
After following these steps, the language in Firefox should be changed to the language you selected. Keep in mind that some websites may not support the language you selected, in which case the website will still appear in the original language.