Ahh the wedding speeches. When you have been to as many weddings as I have, you've seen your fair share of great wedding speeches. Unfortunately I've seen more than my fair share of terrible speeches too! It's so much easier to photograph a good speech, largely because of the reactions that you get from the people who are listening intently. From this bride's reaction, it's easy to see that the best man is really delivering on his speech.
It's easy for a wedding photographer to become transfixed on the people speaking when taking photos, but the best thing to do most of the time is turn your lens towards the guests. The reactions are priceless, and the emotions on display, especially if being shown by the bride or groom are great memories from the big day.
When it comes to photographing wedding speeches I try to stay out of the way as much as possible, but at the same time positioning myself in such a way that I can photograph the person or people speaking as well as being able to photograph the wedding guests and their reactions. A long zoom lens makes this a lot easier, allowing me to cover people at multiple distances. Shooting with a fixed or 'prime' lens would mean moving around the venue a lot more and becoming a distraction.