Everyone loves funny wedding speeches so if you want to have funny memories from your wedding you should definitely choose them for your wedding speech. Please bear in mind that a lot of wedding speeches have been ruined by bad jokes, so be cautious when deciding to do one. Here's an example on how not to start your wedding speech:"Adolf Hitler once said...".
So what do we have to do to create funny wedding speeches? In the beginning, understand your audience. If your audience is intimate as in only close family members and friends you will know already what type of people they are and how they will understand a certain type of humour. Reflect the humour in certain situations and not on people as this can make them feel unconfortable about something embarrasing that happened to them. This does not mean that you can't use some mother-in-law jokes, blonde jokes or priest jokes, as these kind of jokes are common and everyone can undestand the humour in them without relating to the story just because they have blonde hair for instance.
Also, self-deprecating jokes prooved to be very successful at weddings.
Here's a funny self-deprecating joke that you can use at your wedding:"When I was younger, the neighbour's kid was terrified of me.One day I got close to the kid and told him: Don't be afraid, little human! I don't eat children...on Sundays!".
In-jokes are also good for funny speeches if both families are from the same community and they know each other for some time now.
Word play is recommended when the audience speak the same language, and if there are people in the audience that does not speak you language you probably should not use word play. They could be funny to someone else but in these situations not everyone will enjoy them. Consider this aspect if there are too many non-english speakers, for instance, in the audience.
This beeing said, I hope my information vas valuable to you and good luck in picking the right funny lines in your wedding speech.