This wikiHow teaches you how to change the keyboard input language on a Mac.
Step
Step 1. Click the Apple menu and select System Preferences…
It's a black apple icon in the upper-left corner of the screen.
Step 2. Click the Keyboard option
Step 3. Select the Input Sources tab at the top of the dialog box
Step 4. Click the option which is at the bottom left pane of the dialog box
Step 5. Click the desired language
The available languages are displayed alphabetically.
Keyboard input languages that have been added will appear at the top of the list
Step 6. Click the desired keyboard/input style for the corresponding language
The input style will be displayed in the left pane of the dialog box.
An example of a keyboard layout will be displayed at the bottom right of the screen when you click on an input source
Step 7. Click the Add button
Step 8. Check the "Show Input menu in menu bar" option at the bottom of the dialog box
After that, a flag icon will be displayed on the right side of the menu bar.