Half moons/Dots in strange places (hindi)
Why are there half moons and dots on top of words that don't seem to pronounce them?
में seems to be pronounced more lie मे, but I've heard this has something to do with nasalization (supposed to be pronounced "main"). If so, how do you pronounce it?
But that still doesn't explain why मुँह has a dot and a half moon (doesn't a dot add an "n" or "m" sound and a half moon add an "a" sound?)...Can someone please explain this?
Before some consonants, they do add a म न ण or ङ sound (that's why हिंदी can also be written as हिन्दी, and मुंबई can also be written as मुम्बई).
In other cases, like मुँह and में, they simply nasalize the vowel. This means that when you pronounce the vowel, you allow some air to escape through the nose, like in the English exclamation "uh-huh". Although में is often romanized as "mein", the "n" here doesn't represent an actual n sound like it would in English - it represents nasalization of the vowel.
The "Chand Bindilu" (half moon w/ dot) and the "Bindilu" (Dot only) produce the exact same sound. The Chand is only included if there is room for it, i.e. मुँह में. There is not room for the Chand on top of में.
As far as the pronunciation, for a new learner when the Bindilu is in the middle of the word produce a full "n" sound i.e. हिंदी hin-di. When the Bindilu is at the end of the word (or before an ह because these are rarely pronounced at the end of words) then do not produce an "n" sound i.e. में may. In reality there is a very soft "n" sound, but if you say a hard main you will not be understand. The very soft "n" sound is being produced because as you say में your air should be passing through your nasal cavity instead of your mouth cavity. This naturally produced a very soft "n" sound. This can be difficult for learners, myself included. My wife has worked hard to produce these sounds accurately and the native speakers most certainly appreciate and notice her efforts.