The bridegroom usually speaks after the bride’s father, who almost always concludes with a toast to the bride and bridegroom.
You reply, on behalt of your wife and yourself. There is no set length of time for you to speak and no hard and fast rules of what to say. Do not be afraid to be brief, that is often preferred by an audience. If gifts are to be given out it is usually best to present them as you mention the recipient, so the speech continues to flow well. The bridegroom traditionally finishes by proposing a toast to the bridesmaids but you may think another toast is more appropriate… such as to your lovely wife!