Many of the consonants in the English language are pronounced using the teeth. You can't speak well without good teeth.
For example, "t" is made with the teeth, so most British have trouble saying it. If they drive into a lake they will say "my moh'ercar is at the bah'um." Others try to compensate for this by overpronouncing "t" with a spit. "My mo-t'ercar is at the bah-t'um."
Normal people of any language treat a hard (unvoiced) stop followed by a vowel and soft consonant by voicing the stop. Thus we normal people say the "t" like "d." "My modercar is at the boddum." British people don't have the glottal dexterity to do that.