Afraid to open my mouth to talk when someone is making eye contact with me

Afraid to open my mouth to talk when someone is making eye contact with me I will wait till that person looks away before I start my sentence or I will say short phrases. It’s almost like a freeze response. I also feel super conscious of my mouth and I tend not to open my mouth wide enough when I speak. Anyone got tips on how to overcome this? I’ve tried reading a book loudly and exaggerating my mouth but when it comes to actually speaking to someone, I freeze.