You can change to virtual desktop two using the following command line argument:

wmctrl -s 2

Thus executing

wmctrl -s 2 && setxkbmap en

should switch your to desktop 2 and change your language to english as suggested in your example.

You can use a keybinding program like autokey, or KDE custom shortcuts to set a keybinding for the above command. Alternatively, you can save the above command to a text file ending in .sh, and then make the file executable to have a clickable script that will switch desktops and change languages for you.

should switch your to desktop 2 and change your language to english as suggested in your example.

Switching activities is a bit more lengthy command.

Going to go to the next activity is simple enough using:

qdbus org.kde.kglobalaccel /component/plasma_desktop invokeShortcut "Next Activity"

However to switch to a specific activity, you must fist know it's ID which can be obtained by:

qdbus org.kde.kactivitymanagerd /ActivityManager/Activities ListActivities

Once you know the activity id you can switch to that activity via:

qdbus org.kde.kactivitymanagerd /ActivityManager/Activities SetCurrentActivity activity-key-in-previous-step

then couple that with the '&& setxkbmap en' command as shown above when switching virtual desktops to have activity switching coupled with a language change.

Also of note:

export LC_ALL=C

will change the system language to english