(almost) no question is a stupid question. Yours is not stupid.
There is nothing for you to say as a beginner in Judo, when you begin randori, when you bow in or out of class or the dojo, never really. Your head sensei or another black belt will typically begin the class with a formal bow towards a picture of Jigoro Kano (the founder of Judo) located somewhere in your dojo, and then to your sensei and possibly a line of other black belts (all of whom are really senseis as well as far as you are concerned). Shia are always started and controlled by a referee, who says lots of things, but you have no formal replies to him/her or your opponent. Randori is sometimes started by somebody telling the whole class to start, but again you have no formal reply.
About the only sound you should be making aside from breathing heavily is your kiai. Get used to yelling or at least grunting loudly when you apply a lot of force, either during a critical moment of a throw, during a ground move that requires lots of force, and even (and this works surprisingly well sometimes) during applying kuzishi. Sometimes when you find a good time to just pull, push, or torque somebody to set them up for a throw a good kiai can both startle them and add power to your own move. As you will hear a billion (no, that's not enough) times depending how long you continue to practise judo, kuzushi is sooo important to executing a good throw. No kuzushi, no throw.
If any of these terms are unfamiliar to you, or if you don't know who Jigoro Kano is, which is all quite normal if you have only been at it for a month or two, you should do as someone else mentioned, go to your sensei and start asking questions.
One thing I have found. There is really no reason to feel silly in front of anyone unless you truly know you have done something stupid. There may always be people who try and make you feel silly, but thankfully in judo we can just get better and then throw these people around. If you still feel silly asking questions, might as well do it in the dojo because it can't really have anything except a positive effect on your life as you will ultimately learn something about judo or yourself.
I hope you enjoy Judo and stay with it for a very long time.
You can't control the waves, but you can learn how to surf.