All the vowels in Hindi--except for ऋ /ri/--can be nasalized, meaning they can be pronounced with as a nasal quality (as if you have a cold).  The sign to indicate this is called the chandrabindu ँ, which is added above a vowel or consonant:

हँसी (hãsī) laughter:


हाँ (haaN): yes:



For vowels that attach ABOVE to letters, the full ॅ (chandra or moon) is not added--there is not room--but rather just the bindu (dot), which is added just to right of the vowel sign:


किं, कीं, कें, कैं, कों, कौं


Some people will not write (or type) the full chandra (moon).


In some words, the bindu (dot) will appear as a replacement for any of the nasal sounds (ङ, ञ, ण, न, म) when they are found as the first letter of a conjunct.


Some example words are:


हिन्दी  =  हिंदी  Hindi

अण्डा  =  अंडा  Egg

लम्बा  =  लंबा  long, tall