Why are there no new languages?

Being a nerdy type, I usually learn a new programming language or two every year.  Many programming languages are meant to be improvements of previous languages.  Others are created to tackle specific types of problems.  There are new programming languages being created fairly regularly.

Compare this list of programming languages to human spoken languages.  Both lists contain some “dead languages”, but to me, the difference is the list of programming languages is growing, where human languages are shrinking.

Is human language a solved problem?  Is there no place for an evolved language to be created?  What if we took the number system from Chinese, the verb conjugation from English, and the pronunciation rules from Spanish to create an evolved language?  Wouldn’t that be useful?

Kind of like Newspeak, but less totalitarian and more altruistic.