The Document-Specific Language Problem
If you use multiple keyboard languages on your Mac (e.g., English and French, or English and Japanese), macOS has a feature designed to be “helpful”: it remembers which language you were using in a specific document. For example, if you are typing an email in French using the Mail app, but switch to Safari to search for something in English, your keyboard switches to English. When you click back to Mail, macOS automatically switches your keyboard back to French. For bilingual users who constantly alt-tab between applications and prefer to manually control their keyboard state, this automatic background switching leads to hundreds of embarrassing typos.
How to Force a Global Keyboard Language
To stop macOS from changing your keyboard language based on which window you click, you must disable document-specific input sources, forcing the entire operating system to use a single, global language until you explicitly change it.
1. Click the Apple logo () in the top-left corner of your menu bar.
2. Select System Settings (or System Preferences on older versions).
3. In the left-hand sidebar, scroll down and click on Keyboard.
4. Locate the “Text Input” section on the right side.
5. Click the Edit… button next to “Input Sources.”
6. A new panel will appear. Look at the options listed at the very bottom.
7. Untick the checkbox labelled Automatically switch to a document’s input source.
8. Click Done.
The Global State
With this setting disabled, the keyboard language flag in your menu bar (e.g., the US flag or the French flag) now dictates the language for the entire computer. If you set it to English, every single app you click on will type in English. The language will only change when you manually press your designated input-switching shortcut (such as Control + Space) or click the flag icon.