Bengali for English course and a Hindi for Bengali course?
There is already an English for Bengali course in the incubator. However, seeing as Bengali is a widely spoken language (especially in Bangladesh and India), it may be essential to have a Bengali for English course so people can understand one another, especially if they are visiting Bangladesh or India.
Also, a Hindi for Bengali course might also be useful. This way traveling Bengalis can understand Hindi and will easily be able to communicate with ease. (Also, you can understand Motu Patlu).
Anyways, I feel both courses are essential for people traveling to Bangladesh or India.