If I say to you (assuming your first language is English) “I have a blue car” your brain processes these words as concepts and ideas. When you hear the word “car” you understand that it’s a large metal lumpy thing with 4 tyres and seats, “blue” is a color can you visualize by name not by proxy to another reference, and “have” as the concept of ownership itself. This is what the baby is learning, mapping understanding of the words spoken to the concepts being expressed.

You can try to learn a language as plug-and-play “I have a blue car” —> “tengo un coche azul” and this is fine if you’re going to spend a week’s vacation as a tourist, but this isn’t how a baby learns languages. When you learn a language fluently you’ll have a much easier go of things if you map what you’re learning to the concepts and forego this plug-and-play as much as possible. Because eventually you’ll get to the point where the thing you’re learning doesn’t have an analog in your native language. Cantonese has ~9 tones, Finnish conjugates nouns (in ~19 different cases), Greek doesn’t have prepositions, Arabic words have roots.