Wedding audiences are forgiving
Prepare some words, speak them clearly, don't offend the bride and don't go on too long.
By their very nature weddings are happy events, therefore attendees of weddings tend to be in happy mode themselves. Everyone is out to have the very best time possible. The feelings of love, nostalgia and sentiment expressed by the happy couple at the wedding ceremony remain in the hearts of the guests as they sit down to the wedding meal, chat to people they have perhaps not seen in decades, as well as meeting new people and enjoying a glass or two of champagne.
All of the above means that, for the speech maker, wedding guests are about the most forgiving audience on the planet. The wedding guests sincerely want all speeches to go down well, without hitch and with a little bit of humour. No one wants the wedding glow to be tarnished by an awkward speech or jokes falling flat, so if it's a sympathetic audience you are looking for, look no further than the wedding guests.
If you stumble over a few words, go blank for a moment or otherwise 'mess up' your carefully rehearsed speech, worry not, the magnanimous wedding guest audience will forgive you. They are willing you to do well, willing you to strike the right chord, be funny, make that perfect speech but small anomalies they will forgive.
Rarely, if ever again, will the speech maker have such a sympathetic audience as has the wedding speech maker. In remembrance of this it is always a good idea, if you are the best man or otherwise in a position of thanking key players who contributed to the success of the wedding, to have a list of the names of all those who should be thanked. This prevents anyone feeling omitted and avoids the possibility of hurt feelings and people becoming offended.