Let me repeat
he is not involved in the development of Bengali culture, language, food, dance
Why, as a Bengali, will I be interested in him ?
1) Please understand one thing, there was no such Bengali as it is now in the Bengali newspapers, books or magazines at the time when Bakhtiar came to Bengal sometime in 1203 AD. He lived only until 1206 AD when he was killed by one of his generals.
2) In reality, Bengali was not even in the mother's womb at that time, although there are some hints that this language was developing step by step when one reads the PODABOLIs written by Buddhist Monks about 1500 (correct?) years before.
3) When after the death of Nawab Alivardy Khan in 12 April, 1756, Sirajuddoulah was sworn in as the new Nawab, Hindu and Muslim Zamindars were invited at his coronation. The Invitation Letters (NIMONTRON POTRO) for the Hindus were written in Sanskrit. On the other hand the Muslim elites were sent Invitation Letters (or DAWAAT NAMA) written in Farsi.
You can see that Bengali language was not at all developed even in 1756. It was developed only after 1805 when Fort William College was established in Calcutta for the purpose of teaching English language and literature to the black natives. However, the Padres demanded to learn also Bengali, so that they can preach Christianity to the black natives.
Principal Kerry hired very highly qualified Hindu Pundits, and one Tarkalanker (with due respect, I do not remember his first name) was employed as the Dean of Bengali deptt. The five Hindu Pundits tried to teach Bengali, but they failed because there was no Bengali grammar, except a few paragraphs written by the Portugese Baniyas in 1870s.
People have to understand that it is very difficult to teach a foreign language to a foreigners without the help of grammar. The Pundits tried to find out literatures written in Bengali. They found a few poetries, such as Purba Banga Gitika etc, but they could not find a single trace of prose literature, not even a single letter, in Bengali.
These Pundits, led by Tarkalanker and Kerry, compiled the first Grammars on Bengali. Iswarchandra Vidyasagar made quite a few corrections at a latter time during 1840s. During and after this period, Bengali language saw its heydeys in literature, essays and poems. Finally, Tagore received the Nobel Prize in literature and made our language famous throughout the world.