It can be hard not to roll your eyes when you hear couples using baby talk and pet names. Yet, you might find yourself doing the same thing with your partner in private. Don’t feel strange—this sort of communication is actually the mark of closeness in a romantic relationship. So, the more couples use this silly language, the better. Much of this practice can be traced back to babyhood, during which parents imitate the first sounds babies make. Among these sounds are “ ah” and easy letters to pronounce like b, m, and p.