I was born and brought up at Bangladesh. Being raised in an defence environment, i know Bangla very well along with it’s regional derivatives.
Bangla is a very easy language. The best way to excel this language is to keep practising it with someone. Another efficient way to learn Bangla is to referencing it with the other languages that you already know. For instance, if someone knows English, he will definitely know what are parts of speech, there and other basic concepts of that language. So, we can refence them to their Bengali alternatives, which will make it very fun and easy to replicate and learn