In summary: The interplay of meaning and axiomatic machine mathematics, captured by the difference between $\models$ and $\vdash$, is a subtle and interesting thing.
What is the meaning of the $c$ in $C_c^ {\infty} (\mathbb {R})$?
Chôlito bhasha (চলিত ভাষা "running language"), known by linguists as Standard Colloquial Bengali, is a written Bengali style exhibiting a preponderance of colloquial idiom and shortened verb forms and is the standard for written Bengali now.
Bengali people are the majority population of Bengal, the region of northeastern South Asia that generally corresponds to the country of Bangladesh and the Indian state of West Bengal. The Bengalis speak dialects of Bangla, as they call the Bengali language.
Bengali exhibits diglossia between the written and spoken forms of the language; two styles of writing, involving somewhat different vocabularies and syntax, have emerged. The Bengali writing system is the Bengali abugida, a cursive script which is a variant of the Eastern Nagari script.
Bengali (বাংলা) Bengali is an eastern Indo-Aryan language spoken mainly in Bangladesh and northern Indian. There are about 250 million native speakers of Bengali, and another 41 million people speak it as a second language.
Bengali, or Bangla, is an Indo-Aryan language spoken predominantly in Bangladesh and in the Indian states of West Bengal and Tripura by approximately 250 million speakers.
বাংলা ভাষা - Bengali language - Wikibooks, open books for an open world
The Mango Languages app has a fantastic introductory course on Bengali, and Mondly also has a Bengali course. Part of the Linguaboost Bengali course can also be found for free as a podcast.