Contrary to popular belief, hearing your own voice through your own anatomical features is, at best, a minor contributor to this effect, as bone conduction of sound is not the main physiologic factor in how we hear and interpret auditory stimulation.

Before you start to vocalize, you automatically trigger your pre-vocalization reflex, in which cranial nerve VII contracts the stapedius muscle to pull on the stapes in your middle ear, and simultaneously, cranial nerve V contracts tensor tympani to pull on the malleus which tightens the tympanic membrane. This effectively dampens how you hear your own voice.

This is the main reason why you sound so different to yourself when you hear a recording of your voice–you are finally hearing yourself without an operant pre-vocalization reflex. This also explains why patients with Bell’s palsy (lesion/damage in cranial nerve VII) often present clinically with the complaint that they suddenly sound different to themselves.