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This Sanskritised form of Bengali is notable for its variations in verb forms and the vocabulary which is mainly composed of Sanskrit or tatsama words. It was mainly a vocabulary making it easier for literary works in Sanskrit to be translated and understood at that time. Notable among them was Iswar Chandra Vidyasagar, who standardised the alphabets and paved the path for literary works. The colloquial usage of Bengali consisted mostly of its Pali base, indigenous Austroasiatic/Tibeto-Burman/Dravidian deshi, Persian and Arabic words embedded into the vocabulary. As a result, the Hindu pundits chose the path of sanskritisation to make a "pure" language which was not to be used in day to day conversation but would be used as a modern representative of classical languages into which the works of Sanskrit literature can be translated. This shifted Bengali from its Pali roots towards Sanskrit. This in turn increased the commonality in Bengali vocabulary with other Indo-Aryan languages, such as Hindi and Urdu.
The development of Sadhu Bhasha and Chalita Bhasha were more or less a parallel development. By the time Ishwar Chandra Vidyasagar and Bankim Chandra Chattopadhyay created the ground work for Sadhu Bhasha, Kaliprasanna Singha, Peary Chand Mitra and others realised the strength of the Chalita Bhasha.
By the time of Rabindranath Tagore, the Sadhu (pure) part of Sadhu Bhasha had largely waned into just a set of verb forms and in a decade or two he himself would choose Chalita Bhasha as a literary form of Bengali.
Dr. Radha Nag's book Atmaghati Nirad Choudhuri আত্মঘাতী নীরদ চৌধুরী (Suicidal Nirad Choudhuri) appears as the last Bengali book written in Sadhu Bhasha.