The various languages of the keyboard are actually printed on the keycap. Normally, if the key cap is printed in AZERTY French, the computer system selects the French keyboard. At this time, hit AZERTY, and the system displays AZERTY. But if the English keyboard is selected in the computer system, then hit AZERTY, the system will display QWERTY. So, the language on the key cap just helps us remember the function of each key. In fact, you can change the keycap to any language, or paste the required language sticker.
These two posts can help you understand.