There's a number of vowel distinctions who are preserved in the writing system but they are not pronounced as such in modern spoken Bengali or Assamese. Some of the vowels have different sounds depending on the word. All of these vowel letters are used in both Assamese and Bengali. The script presently has 11 vowel letters, used to represent the seven vowel sounds of Bengali and eight vowel sounds of Assamese, along with a number of vowel diphthongs. In this and other articles on Wikipedia dealing with the Assamese and Bengali languages, a Romanization scheme used by linguists specializing in Assamese and Bengali phonology is included along with IPA transcription. Since around 2001, there is work to develop Unicode fonts, and it seems likely that it will split into two variants, traditional and modern. It seems that the need to typeset Eastern Nagari on computers will influence greatly its standardization. Among the various regional variations within this script, only the Bengali and Assamese variations exist today in the formalized system. While efforts at standardizing the script for the Bengali language continue in such notable centers as the Bangla Academy in Dhaka ( Bangladesh) and Paschimbanga Bangla Akademi in Kolkata ( West Bengal, India), there isn't a uniform spelling for Bengali, as many people continue to use various archaic forms of letters.
Thus, learning to read the script is complicated by the large size of the full set of characters and character combinations, numbering about 500. They are represented by different and sometimes quite irregular characters. Like Devanagari, Eastern Nagari also uses dozens of consonant clusters. There is a rich legacy of Eastern Indian literature written in this script, which is still occasionally used to write Sanskrit today. It was also used by the later Ahom kings to write the Buranjis, the Ahom chronicles, in the Assamese language. Madhava Kandali used it to write the Assamese Ramayana in the 14th century. Sankardev used the script in the 15th and 16th centuries to compose his writings in Assamese. The vernacular dialects of Pali eventually evolved into Bengali, Assamese and other related languages. After the medieval period, Pali succeeded Sanskrit as the new written language in the region. In this region, Hindu epics ( Mahabharata, Ramayana etc.) were written in older versions of the Eastern Nagari script in this region.
The script was also used to write Sanskrit. The Bengali-Asamese script wasn't created to write a certain language, but it was the main script in the eastern regions of Medieval India.