We exist in a time when celebrities will name their kids after fruit... I love "Leo" as a shortened/nickname, though it's among those that work fine, imo, as a first name. Some do, some don't.
Leo Dicaprio? Probably not, since he IS a Leonardo and calling him Leo would be done by those speaking more informally... while adding the surname is automatically formal and comes across slightly odd saying both together in a case like that.
|