When I sing the Roof of my mouth vibrates and so does my lips and throat is that normal?

Well some technique experts will say yes. The soft palate is important according to them. Personally when my teacher says lift the palate I just inhale on a bratty 'eh' sound with my cheeks lifted (always no voice happening on the inhalation-the bratty eh is a position but you can kinda feel friction when air is drawn in) under my eyes. This gets me to feel cold air on my palate just like when sucking on a mint. My jaw isn't dramatically dropped but my cheeks look lifted. After that I just keep the zygomatic position and then sing with that pharyngeal vowel. Then again this technique is very operatic or classically based so I don't really recommend it. If you want to try it go ahead but keep in mind you might snort in the beginning if you're unfamiliar to the sensation. Also a helpful tip to begin with is to keep this cheek position but inhale on an 'ng'. This will get you to nose-breathe with your mouth open. Once you go to sing you will hear a click or a slight K, and then you'll start singing. This helps with the lifted palate and the vocal ring/buzz/resonance. Hope that helps.

I didn't know the roof of a person's mouth vibrated.

i want to experience it