You are free to come and observe without feeling pressured to speak. The environment is friendly and supportive. There 0 - 2 prepared speeches, and with the remaining time individuals can speak for 1-2 minutes about a topic that will be given impromptu. At the end, feedback is given to all of the participants (how long did you speak, grammer, filler words, etc.).
If you choose to become a member you'll find that the self-paced program allows you to build confidence with each speaking assignment.
Guests are allowed to visit as often as they like before becoming a member, and guest can participate in the impromptu speaking portion of the meeting. One thing that you'll love at Toastmaster meetings is the applause. Once you decide that you are comfortable enough to speak, you will be applauded for your efforts.