Too Long; Didn't Read
A bunch of languages already appeared in the 21st century. Swift, Kotlin, and Go are probably among the most popular. However, the distinct feature of 21st-century language design is the absence of any distinct features in the languages themselves. The best thing about any of these is that you can spend a weekend and claim to learn a shiny new thing without actually learning anything new. They don’t have anything new in them at all; they are all made by the “something done right” formula, this something being Objective-C, Java or C.