Bitcoin - Language of Money can be an interesting language to learn as a next step
Lol. We are talking about real language here mate unless you want to go learn some coding language. Nevertheless, that cannot be used for communication, so unless you are lost to what the OP is asking, then I am not sure if you have anything tangible with that.
I did not choose any option though because I was stuck with learning Chinese and Japanese, based on so many reasons that make the two of them important, but if I am to choose one first, I will choose Japanese, since crypto related, they just seem to embrace technology pretty fast.