It wasn't the only aspect/concept considered as many nation's aspects/concepts were considered.
And British law wasn't the only place where "legal terms", or such similar concepts, such as natural born and naturalized were used.
That's like saying neither France nor Germany had a law governing armed robbery, murder or rape.
That alone says something.
Most of our founders were born as natural born subjects of England. Many were lawyers who used and studied English law. The terms of law they were most familiar with - and utilized - were terms used in English law - those being “natural born” and “naturalized”.
But that is not the crux of my argument.
The U.S. Constitution only makes mention of two types of U.S. citizens that one could currently be - natural born or naturalized.
Are we going with what the U.S. Constitution ACTUALLY says - or what you want it to say via penumbras and emanations?