Learn English – ny vs. Are there any

This is a difficult area of English for foreign learners, and I’m afraid you’re not going to understand it fully from a few answers here. Very briefly, you use the present perfect continuous form to talk about events in the recent past, particularly activities that have not been completed. The form is often found with the prepositions ‘for’ and ‘since’, as in ‘He’s been speaking for a very long time’ or ‘I’ve been working non-stop since this morning’.

Here are a few examples contrasting the present perfect with the present perfect continuous:

'I’ve done my homework' (it’s finished) / 'I’ve been doing my homework' (it’s not finished)

‘I’ve drunk my coffee' (it’s all gone) / ‘I’ve been drinking my coffee’ (there’s some left)

‘It’s rained every day since the weekend’ (repeated rain) / ‘It’s been raining all day’ (continuous rain)

Your own examples don’t really illustrate the use very well. You wouldn’t say ‘I have learned English language in the past few weeks’, because that suggests you’ve finished your studies and you don’t need to do any more. That’s unrealistic. No one learns English in a few weeks. I think these two examples might show the difference more clearly:

‘I have been studying English for two years’ (I’m still studying it)

'I have studied English, but I don’t speak it very well' (I studied it at some time in the past, but am not studying it any more)

There's one significant point that I don't think was picked up in the other answers.

Be mindful of doing something indicates that you should take care to ensure that you do something good, or to be aware of the possibility that you might do something unintended. In other words, what you're mindful of is the outcome. Examples:

• Be mindful of using verbs in your sentences tells you that you should be careful to make sure you include verbs in your sentences.
• Be mindful of upsetting people when you talk about politics in public tells you that you should consider the possibility of upsetting someone if you talk about politics, and be careful not to.

On the other hand, being mindful when speaks about the action you're performing rather than its outcome. - Be mindful when using verbs in your sentences assumes that you're using verbs in your sentences, and tells you to be careful when doing so. It doesn't specify of what you should be careful. - Be mindful when talking about politics in public assumes that you will be talking about politics in public, again without specifying why you should be careful.

I am straying into opinion in adding this one last point: I personally think that writing of being mindful when without adding what to be mindful of is almost always poor English, as it doesn't indicate how to be mindful. Except in a very general sense of "being intentionally aware of yourself", mindfulness really requires an "of" to be meaningful.