The majority of the time is not learning the language, it's the learning the framework. So it really depends on what's you're doing.
Things that make it take longer.
UI heavy tasks
Anything that requires heavy customization of large framework.
New projects.
Usually in a month I can come up to speed where I'm contributing to an existing project, without doing any heavy framework customization. 6 months until I feel like I can handle pretty much any task, just need a little more time than an expert. And after a year I can probably do most things quickly.
Things that make it take longer.
UI heavy tasks
Anything that requires heavy customization of large framework.
New projects.
Usually in a month I can come up to speed where I'm contributing to an existing project, without doing any heavy framework customization. 6 months until I feel like I can handle pretty much any task, just need a little more time than an expert. And after a year I can probably do most things quickly.