Question: how many words have all 5 vowels?
Answer: Eunoia, at six letters long, is the shortest word in the English language that contains all five main vowels. Seven letter words with this property include adoulie, douleia, eucosia, eulogia, eunomia, eutopia, miaoued, moineau, sequoia, and suoidea. (The scientific name iouea is a genus of Cretaceous fossil sponges.)