@Stinley A British friend of mine named her children with four names. First, middle, mother’s last name then father’s last name. I think her children technically have two middle names, not two last names. It would have to be like that if they want to be filed under the correct last name that they actually use, which is only their dad’s surname. They were born in America, but they did live several years in England, and then the family returned to America. Their legal names might be technically different in the two countries (meaning I am not sure if the mother’s surname is listed as a middle name or last name in England) but they still legally have all four names.
A man who worked for me had a hyphenated last name and I know part of his family was from Scotland. I wonder if that had something to do with using two last names? He was Jamaican. Jamaican-American. It is very unusual in America for a man to have a hyphenated last name. I have no idea how common it is in Jamaica. I also don’t know if the name was handed down on the paternal side, or if that was actually a mix of his mother and father’s surnames.
It’s more tricky now in America in that middle names have become more important for things like travel and identification. It used to be you could just use a middle initial, but now you must have your entire middle name spelled out on government ID’s. Full legal name. Some people did not use their middle names at all, even their signatures developed from childhood did not use a middle name or initial, and now in the last ten years middle names are more important if you have one. If you don’t it’s fine. My husband doesn’t. His legal name in his country is two last names, but in America, where we live, he just has one.