There are many types of baby cries, but you're likely to be able to spot the subtle differences between them before you know it! For most babies, a hunger cry starts with a small whine or whimper, before building in intensity if you don't notice in time that they're hungry!
You might also see some specific behaviors: for example, if your baby's tongue sticks out or they're looking for a breast while they're crying, they're likely to be hungry.