Looking for 75th anniversary speech ideas

My folks are getting ready to celebrate their 75th wedding anniversary and I have the honor of giving a speech to honor them and the occasion. I am the youngest of 4 and the only one of their children to be in attendance. I need ideas on how to pull this together. I'm not a public speaker. I prefer written communication but after several years in a technical career I write like a lab report or shop manual. I thought of outlining all of the history and societal changes they have been through (their first home cost $10500 for a...