• Android
• iOS
• Desktop

Android

To change the language:

1. Open Signal.
2. Tap your profile to go to Signal Settings.
3. Select Appearance.
4. Select the last item Language. 
5. Scroll through and select the language for it to apply immediately.

iOS

iOS 13 & iOS 14

To change the language:

1. Follow steps from Apple's support page to ensure the language is enabled in iOS Settings.
2. Go to iOS Settings > Signal.
3. Select Language.
4. Scroll through and select the language for it to apply immediately

Desktop

Locales and languages for Signal are now based on your system preferences of your computer's operating system. This should result in better default behavior when multiple languages are configured.

To change the language:

• Within the Language & Region settings on your computer, the top language from the list of “Preferred languages” will be used for Signal Desktop, regardless of what is selected for the “Windows display language” or “Country or region” settings. 
• Change the top language in the list.

To manage spell check:

1. In Signal, tap your profile >  Preferences...
2. Under Chats, select or deselect Enable spell check of text entered in message composition box.