[1] After the conquest of Nadia in 1204 AD, Islamic rule began in Bengal, which influenced the Bengali language.
It marked the renaissance of Bengali, as well as incorporating borrowings from European languages.
These included dialects of the Magadhi (or Gaudī) group, which were primarily spoken in the region between Bengal, Bihar, Orissa and Assam.
This influence, in a contact situation has an impact primarily in the vocabulary of Bengali language and as a result not only tatsama words are accumulated in the Bengali vocabulary but also this lexical diffusion resulted in diachronic change by developing ardhatatsama and tadbhava words.
The people of ancient Bengal initially spoke a Prakrit language, which was known as Magadhi, or on the contrary, Gaudi.