types of human "sounds" and reactions

So, in the past days I was searching for some intersting vocab in our script and I came across some illustrative words, such as: stammer, snigger and squeak. A person who stammers is normally quite annoying to talk to, although you know it's not there fault to speak like that. To squeak reminds me of the door in our old house who squeaked open every time you entered the main room. Snigger is something I connect with my teenage schoolmates who did this each and every time a cute boy strolled aroung the corner.
A reaction which is typical for a half of my family is scowling - my father and my sister do this constatly when tired, bored or in the process of getting angry. Consequently, my father's forehead is an embodiement for wrinkles.