There's a new ui.bn.txt localization file for Bengali added to the ui.zip collection of localization files. It's also appended to this post.
Hindi and Bengali are the most widely used languages in India, a rising IT tech powerhouse, and are the fourth and fifth, respectively, most widely used languages in the world. Adding Bengali as a localization file together with Hindi provides native language support for almost 600 million people.
This is the first of two independent Bengali localization efforts now underway. It is an extensive translation to 171 build level. The next translation will take localization to 171.1.