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