It probably depends on how we are defining "learned". Does it mean memorizing all the functions in language x's stdlib? Is it learning the grammar of the language? Is it coding a project of x many lines of code? Have you learned a language when you can write a compiler / interpreter for that language?
The concept of "learning" a language is so hopelessly ambiguous it has almost no meaning to me.
I would say that I know enough of many languages to use them professionally, but I have deep knowledge of very few.
I believe that "learned" means "learned enough to work professionally with".
Deep knowledge of a language is always very desired, but on the real world very few programmers have it, or even need it. (Not to mention that "deep knowledge" is a very abstract concept on its own too, lol)
Not every professional developer can, for example, write a framework or a compiler from scratch in their language of choice, but they're still productive and fundamental to their team...
The concept of "learning" a language is so hopelessly ambiguous it has almost no meaning to me.
I would say that I know enough of many languages to use them professionally, but I have deep knowledge of very few.