I use https://exercism.org/ with new languages to get a grasp on syntax and see examples that other people have submitted.
It's far from a true comprehension of the language, but it is really helpful to tackle problems that I've already done a few times in languages I am more familiar with to help relate concepts and highlight the differences.
I use it to get familiar with various concepts and idioms in languages I don’t know at all, and also for ones I feel comfortable with, where there are parts I’d like to understand and perhaps use in future. It’s incredible!
It's far from a true comprehension of the language, but it is really helpful to tackle problems that I've already done a few times in languages I am more familiar with to help relate concepts and highlight the differences.