I have seen teams using languages traditionally considered "easy-to-understand" assuming that the language being readable is sufficient to replace communication and proper documentation.

I have also seen teams using languages traditionally considered "easy-to-understand" use various forms of meta-programming to customize the code and make it even more easy to understand... eventually reaching the point where nobody except the experts of this specific sublanguage could understand it.

I have seen teams using languages considered hard-to-understand being obsessed with documentation and communication – and others who don't care at all.

I've come to the conclusion that it's a teams thing, much more than a language thing.

I’ve never seen hard to understand language, just hard to understand code. Without exception. Do you have any specific in your mind?