Some words for without thinking are:
a zookeeper or a vet... think before you speak honey
I think a tri-lingual person.
A foot in the mouth guy.
A person who does not speak is called mute or nonverbal.
So you do not call out and be disruptive. You have to think before you speak. If you do not, you probably will not sound very intelligent.
mute
You call them 'mute'.
quiet
A person who can speak two languages is called a bilingual.
If you want to call her do it when you feel comfortable but it is always best to speak in person.
Sorry, but you can't. -Unless you mean the volcano of your emotions. then, you just take ten (10) DEEP breaths and think, think, THINK before you speak. Call it a 'pause' button if you like.
If someone is unable to speak, it's called being 'dumb'.