Formal events, parties and all those social gatherings are a great place for hanging out and meeting new people. However one person will have the responsibility to make sure everything thing is in order and that is the host or hostess. It can be real stressful job; the organizers will be counting on them to make sure the event runs smoothly and nothing goes wrong. In addition for them to be a successful host/hostess they need to not stutter or be nervous around a huge group of people. It's hard job for anyone because of the stress and anxiety it can bring out, but there are ways to help relieve those negative thoughts.
Public speaking is, for many, the most stressful when you're hosting for events and parties. It can be very hard to even say anything without stuttering or sweating and the pressure is on you to let people know what is going on during the social gathering. How you can reduce this stress is to practice your presentation with the goal of speaking clearly, find out what you need to inform the people and add in your own way of presenting it to them. After that record your practice presentation--then you can listen to the whole presentation and see what you can do to correct it. I've done this plenty of times for my speech class and as a result I was more comfortable of talking to a large group of people as time went on. Now I have more confidence when speaking in front of large amounts of people.
Another preparation is to relax. As a host you'll be doing most the work during the event and the level of stress and anxiety can overwhelm you. This can also affect your speech to the audience as well, such as stuttering and sometimes having moments where you suddenly stop and forgot what you're about to say. Take deep breaths and calm down; you're there to direct the gathering and help things run smoothly but do it in your own way. For myself, I always try and make a funny joke or tell them to introduce one another to lighten up the mood. In a way you interacted with the people so now you can give them information as well as introducing yourself.
Whether its a formal event, party or a wedding reception, being a host is an honor but can be a daunting one. It isn't always as easy as it seems. There are a lot of duties involved and a great number of practical aspects to bring attention to but most importantly stay calm and review everything and remember you are there to help the audience feel engaged with, and feel informed about, everything that is happening.