How can we understand what babies are crying about? Does their cry sound different when they are hungry compared to when they are tired?

For me, I will look at the time my child had his last feed and nap. His cries were sharper and more intense when he was hungry, and more to sobbing when he was tired. However, there are times when he was crying despite being fed earlier. That was the growth spurt period when he kept wanting to drink and sleeping patterns changed. I had to check if he had soiled his diapers, rub some tummy oil to ensure was not gas pblm. He continued to cry and by looking at his big eyes, I knew he wasnt feeling sleepy so I made some bm which he drank hungrily. It takes a lot of trial and errors as babies are smart.