This paper investigates the growth and development of Bangla-Hindi Bilingualism based on the Census of India data from 1931 to 2001.The investigation is carried out in the following manner: First of all the census data from 1931 Census was collected and the total number of Bangla speakers and Hindi speaking population (comprising the second largest population in West Bengal) was compared. The status of both Bangla as a first and second language and data for Bilingualism of Bangla English or Bangla-Hindi were collected as per the availability. The observations were then tallied with the data given in the People of India Project. The analysis reveals several pertinent information which may be used to make appropriate language policies in the state and other parts of the country.