Don’t worry about the tangent, I’m a bit of a linguistics nerd. As you will be able to tell by the following paragraphs.
Try making a d sound with your tongue right behind your teeth. Now try making it with it deeper in your mouth, touching the top of your mouth. There’s multiple tongue positions in the mouth that can make d sound. While making the d sound you can also change the amount of air you expel to make the d sound.
This is how a lot of the multiple letters for a single Latin letter work in most indian languages. Explicit characters for each position and often two letters at each consonant position, one for low stress sound at that position and one for high stress.
Sanskrit is an ancestor language for most Indian languages, like how Latin is a parent for most European languages. There are some differences between the modern language alphabets, similar to how German, Spanish, and English pronounce “j” differently. Umlauts and/or accents addded to vowels in some european languages, but not others, etc. But the majority of the letters are the same. South Indian (Dravidian languages, as opposed to north India’s indo-European languages) have alphabets that look very different but the letters have mostly a 1 to 1 relationship with the north Indian ones.