Instructions apply to any web surfing app, Android, and iOS apps.
Just go to your account tweaks.
grab the arrow (Account) on the right side of the Facebook menu bar.

ChooseLanguage and Regionin the left menu pane.
In theFacebook languagesection, selectEdit.
Select theShow Facebook in this languagedrop-down menu, and choose a different language.

SelectSave Changesto apply the new language to Facebook.
These instructions do not apply toFacebook Lite.
Scroll down toSettings & Privacy, and tap it to expand the menu.

it’s possible for you to change this setting, but you do so outside of the app.
OpenSettings, and then scroll down toFacebook.
SelectLanguage, and then choose the language you want.

However, that doesn’t always work so great, plus it’s not permanent.
Below is an example where Facebook is in Brazilian Portuguese.
Go to theFacebook language options.

In theFacebook languagesection, selectEdit(it will be in the current language that you set).
Select theShow Facebook in this languagedrop-down menu and find your language.
Then, selectSave Changesto save the change.

FAQ
Changing your language on Facebook will change the language for the Facebook Messenger website.
To change the language for the mobile app, you canchange the language on your phone.


