[James A Pratt III]

I know the HS 126s had voice radio to spot artillery fire and to communicate with Luftwaffe laison officers on the ground in the early part of the war. I would say both direct contact to troops on the ground and to a headquarters to the rear may have been done. Note senior German officers would sometimes go to the front during WW II to see how things were going and they might have had a radio set on hand to talk to the Luftwaffe aircraft flying over head.
Also for a 109 pilot a Fi 156 is a fairly easy plane to fly and was sometimes used as a hack by some JGs. I hope this is of some help.