The language Bengali evolved over a long period of time. There were various stages in its development:
(1) First stage: Initially, Bengali was not spoken in Bengal and the adjoining areas. In fact, earlier scripts suggest that people from Bengal did not even speak Sanskrit. With the influence of growing commercial ties that were shared with Magadha and Indo-Gangetic areas, Sanskrit and Sanskritic ideas started flowing into Bengal. Over a period of time, Bengali as a language grew out of various Sanskritic influences.
(2) Second stage: As the area was ruled by Muslim rulers independent of the Sultans of Delhi, Persian became the official language here, while Bengali remained the regional language. The language further adopted many words from tribal, Persian and European languages and evolved over the time.