Like, English is a famously difficult language, and Spanish is supposed to be easier. But babies learn English or any language instinctually.
So do babies learn faster if the native language is easier, or do they acquire language at a constant rate depending on their brain development or whatever?


Spanish is phonetic, what you see is what you get. There’s a few rules around the pronunciation of the letter c and (q)u/h not being pronounced, but it’s otherwise pretty standard. Gender in Spanish isn’t that difficult.
English is a complete mess of a bastard language with more exceptions than rules.