dd,
I don’t think everyone is ashkenazim. But right now I am speaking about ashkenazim, not sphardim.
oomis1105,
Why was that more likely to have been spoken that way in the times of the bais Hamikdash? Were some dikduk rules made up later on? Also as some previous posters mentioned, different shvatim had different pronunciations even in the midbar . In that case there is no one correct pronunciation.
Joseph,
I think I remember that temanim are supposed to pronounce gimmel and dalet differently with a dagesh kal.