Everyone has experienced this: when confronted with a recorded version of your voice, your reaction is “I sound like that? Really? It’s not how I sound to me. Eeewwwww.”
First, you’re not alone. Second, you’re not imagining things; you DO sound different to you. This is from Gizmodo.
The voice in your head is a lie. What you hear when you open your mouth is distinctly less velvety than what everyone around hears—and it’s your skull that’s to blame. More specifically, it’s the way your skull vibrates.
Your voice emanates from from the lower portion of your throat, as expelled air from the lungs passes across your vocal chords, which vibrate to generate sound. This sound is then amplified by your voice box, modulated into words by your tongue and lips, and reverberated through the surrounding atmosphere until it enters your listener’s ear canal to stimulate their eardrums and structures within the inner ear—which then convert the analog waveform to electrical impulses that the brain can understand.
However, the inner ear doesn’t just pick up sound from external sources. Vibrations emanating from within your body can activate these auditory structures as well. And when you speak, the rapid fluttering of your vocal chords actually causes your entire braincase to vibrate.
Read the whole explanation here.