Will Windows 10 detect automatically if I physically change the keyboard (the physical object, not the layout) from english to french? [closed]

No, usually Windows can't tell...

As long as you use a standard USB keyboard (not one of those specialty keyboards for Asian languages) Windows just considers it a generic keyboard and depends on the users keymap choice in Windows to determine which character is generated when a specific physical key is pressed.)

So, if you have a colleague that types blind he/she may not even notice you changed it. He/She will still be typing QWERTY even though the keys on the French keyboard are labelled AZERTY.

No. Windows will not be able to determine what the keyboard language is. In order for Windows to know what language the keyboard is, you have to setup the keyboard language in the configuration.

This effectively also means that if you unplug the keyboard (both USB and PS/2 types), and plugin a completely different keyboard, with different layout and/or brand etc, Windows will not see this as a different keyboard when it comes to the language of the keyboard.

So if you exchange an English keyboard for a French keyboard, unless you also change the settings, the keyboard will type like the old one.

The reason this works is because keyboard have a standardized layout. Each key has a unique code attached to the physical button. When pressed, this code is sent to Windows, and Windows then uses the keyboard layout configuration setting to determine what key is pressed. This also means that if you change keyboard layouts, you can suddenly make the right Alt behave like an Alt Gr, or if you setup a Swedish or German keyboard, you suddenly get weird keys on many keys that weren't there before.