Bangla bhasha kothai shikhlen? I'm impressed...Though prayash is Hindi I think? We say cheshta kora.. My Pashtun is non existent. Most of the Afghanis I've met seem to be Dari speakers and Pashtun from Pakistan seem to also communicate in Urdu, at least in my community. Little opportunity to learn!
Happy to help you learn but I'll admit now my 'shuddho' bangla is not brilliant. I think redifflal probably speaks a lot better than myself as being from West Bengal, the dialects from there are much closer to the Nadia based dialect which over the 19th century has become considered the standard.
My family hail from Sylhet in the NE of Bangladesh. Our dialect and Chatgaya Boli from Chittagong probably differ the most from Standard Bengali and are often unintelligible to most including from Bangladesh. Pronunciation is quite different with a lot of fricatives, some vocabulary differences and different grammatical forms.
In the Sylhet region everyone obviously learns Shuddho through the school mediun, but in the diaspora in UK, formal Bengali teaching is lacking so we tend to communicate in our own dialects. I've made an effort to learn and can read and write, but a long way to go.