I'm curious about this assertation. I've also heard that "do one thing and do it well" is a desirable goal and one should offload tasks to other pieces that specialize in that task (e.g. don't write your own crypto, use existing libraries), is there something that makes a programming language different?
In the context of programming languages, dependencies are a property of a programming language implementation. LLVM is not a small system, yet PicoLisp is a small language, which is why it might be considered a heavy dependency. There are scenarios like embedded where having a tiny implementation with little dependency pays off.
Ordinary programs can be very easily maintained by using only the language's standard library, as standard library is often maintained substantially longer than many third-party libraries.