When you're a baby, communicating through words is not a thing. As in the concept that when you're hungry, you just say "I'm hungry", or when you poop, you say "I pooped", is foreign to an infant. Obviously this is because infants haven't learned what talking or words or language are when they have just popped out mere moments ago. And so, this could be easily rectified simply by talking to the infant, by using the words "hungry" and "poop" in front of it and letting it learn to associate things with words. Soon, the baby will have graduated from wails and caws to the power of speech.
But while it is relatively easy to express basic feelings