Reading and writing are one way of learning.
Reading and writing are the primary method of learning in public schools.
Reading and writing are not the only way of learning.
Reading and writing aren't even the best way of learning.
In fact, psychoeducational research shows that children learn best when multiple senses are engaged, when learning is immersed in "real life" and hand's on activities.
So how does learning occur when reading/writing aren't the primary tool?
I read to Helena. We listen to audio books in the car.
We discuss things. I don't really "quiz" her! There's a big difference between quizzing someone and having a totally natural, deep, casual discussion of a subject much like you'd have with another interesting adult. When you quiz a kid they're looking for the correct answer to please authority and get the quizzing task over with (unless they really like quizzes). When you discuss casually, they are engaged, formulating arguments and opinions, learning critical thinking skills, and learning how to effectively communicate their view points. And it's fun!
We live life together! See other post on unschooling/homeschooling to see all of the "subjects" covered through daily life lived in an adventurous and curious way.
I strew her path with many different learning opportunities, allow her to experiment, and encourage her passions.
We go on "field trips" to historical museums, science museums, art museums, historical sites, oceans, forests, wetlands, mountains, and so on.... We explore. We're curious. We discover. I don't give "assignments" and we just enjoy and discuss (see above on discussing vs quizzing).
We learn through audio/visual means. I mentioned audio books above. Recently we listened to the classic novel The Witch of Blackbird Pond. We learned so much about Puritan times and culture, so much more than we'd learn in a textbook. We discussed what it would be like to live in such a strict culture! We also learn through video such as documentaries - Wild China, which is on Netflix, was fun when her dad took a trip to China - and funny instructional videos such as Math Antics. We learn through video games such as DragonBox which teaches all of the basics of solving equations though a game where you have to isolate the dragon box. We learn though shows such as Magic Schoolbus. Sometimes these shows stimulate more questions and we get out some simple library books or do experiments or something.
In short, there are so many different ways to learn where reading/writing are not the primary tools. I'm a big believer in making my kid feel successful and catering to her strengths, while also slowly working on the weakness that reading has been. But I'd rather crawl with the reading then end up with a child who can read on level - but will never again crack a book for the rest of her life unless forced to.