I've toured in all three, enjoyed all three immensely. There's a lifetime of great riding in all three, even avoiding areas that don't suit you. Arid Spain in summer for instance, though I found arid inland areas on gravel farm roads to be lovely in November. And great food in all three, with varied and diverse local variations (this is as important to me as the pedaling).
Flip a coin, knowing that whatever you pick now you'll still have to visit the others on later tours. Seriously.
I wouldn't let lack of language skill deter you from any of the three (or any country anywhere for that matter). You need things, people want to sell you those things, commerce will always find a way if you approach with an open attitude and try your best to learn a little of the language. Conversations with locals happen organically along the way no matter what. And 6 weeks is plenty to get some basics in any language, if you make an effort and spend some evenings working through language books or apps
m2244 I do think you'll get more useful advice if you can outline the time frame, as July vs December will have very different specific recommendations.