Some tips for writing a wedding anniversary speech for your mom and dad include telling the story of how they fell in love, mentioning major events that made them closer or sharing personal observations of how they express love to each other. Some other ideas include adding humor to keep guest's attention and offering a toast to many more anniversaries.
When writing the speech, use your natural language and tone so that the speech sounds personal and conversational. When discussing anecdotes from your parent's past, ask each parent separately about the events before writing about them. This is one way to tell the story of how each fell in love with the other, as each likely has a different moment when they knew they loved the other person. Some other stories to tell include when they had their first child, when they faced a big change or any tradition they maintained to keep their romance alive. Discuss any special things they did for each other, such as buying flowers every week or hiding sweet notes in the other person's lunch bag.
Keep the speech short while still honoring your parent's relationship. Punctuate the speech with a few tasteful jokes. Be genuine and share what their example of love means to you. End the speech by asking everyone to raise their glasses in tribute to the happy couple.