As others have said I wouldn't memorise them. First names are easier. But both first names and last names can vary in spelling. Such as Jeni and Jenny. And Nicky, Nikki, Nicki. Really, even we ask people how they spell their name if it can vary. Surnames can have very complicated spelling or pronunciation. As you come across names, just learn it that way. And maybe you can look up the top ten baby names so the ten most common ones are learned if it will help you.