I have been programming since I was a child, and have little difficulty picking up up new programming languages when required. I have also taught myself to read and play music. However, every attempt of mine to learn a non-formal human language has been a non starter.
Admittedly I have never been immersed in a non-English speaking culture, but even so, I hit a mental wall that I cannot seem to get past. They never 'click' into place the way formal languages do for me.
But I think (and what do I think; I know a little here and there but certainly not conversational in another language) that we can immerse ourselves easily in a programming language, so if we're drawing equivalences, it should be easier to learn a programming language than a spoken one in the same levels of culture immersion -- and most of us are here, aren't we?
Admittedly I have never been immersed in a non-English speaking culture, but even so, I hit a mental wall that I cannot seem to get past. They never 'click' into place the way formal languages do for me.