what do they speak in bangladesh
Languages of Bangladesh. The official and de facto national language of Bangladesh is Modern Standard Bengali (Literary Bangla). It serves as the lingua franca of the nation, with 98% of Bangladeshis fluent in Standard Bengali or Bengali dialects as their first language.
There are a number of different Bangla dialects that are generally grouped according to the various regions in Bangladesh. Due to the British colonization of the country, English is also a widely spoken and commonly understood language in Bangladesh. Besides this, there are 38 languages that are in use in Bangladesh.
Keep in mind though, Dhaka is the capital city of Bangladesh. So, the people who live there are more culturally influenced by the neighboring countries. Our assumption that an average Bangladeshi will speak/understand Hindi/Urdu might not hold up as well in the rural areas.