Hi there,
The problem with common (i.e non-botanical) plant names is that they can and often are applied to lots of different plants.....The plant most usually called "Devil's Tongue" is Amorphophallus konjac, which is a lovely Aroid that I grow in containers in an unheated tunnel since it absolutely hates getting wet over winter. Unless you or a previous owner of your garden was a major specialist plant collector then you most definitely won't have one of these in your garden.

What you may well have is a Dracunculus vulgaris - google the name and see if that fits your plant. It's a close relative and much more widely grown, as well as being happy growing in a sheltered garden.

If your plant looks nothing like this then please see if you can supply a pic and we'll try to ID it for you.