In addition to the regular ABNF formalism governing the Brahmi Syllable, Bengali language admits two more combinations which are unique to Bengali

1. both candrabindu and anuswara /bindu can come together and in proof thereof this word is cited হ্যাঁংচা : Hancha a sweet
   হ ্ যা ঁ ং চা 09B9 09CD 09AF 09BE 0981 0982 099A 09BE
2. a nasal can be followed by a visarga the following example is provided. This combination is attested in Vedic but not in a neo-Brahmi syllable
   হ্যাঁঃ হ ্ যা ঁ ঃ 09B9 09CD 09AF 09BE 0981 0983
   Both cases are rare and have been validated by the Bengali experts who I contacted.