"Turtledoves" is a well-known expression that we would recognize, here in the U.S., but these days simply saying "lovebirds" is much more common. The thing is, calling a couple "turtledoves" is something that was much more common about 50 years ago - or more even, for all I know. So, while we're familiar with the expression... it's more likely to be something heard by/from/about older people than younger people - who are more familiar with the expression "lovebirds".Make sense?