We learn to talk before we can write. When we are learning a new language it is important to remember that the writing does not always correspond to the sounds. For instance, Chinese uses characters that tell you nothing about what the word sounds like. Most languages use a symbol to represent a sound. Even if you don’t know the language you can say the words correctly by learning the sounds of that language. The Finnish Language is an example of that.
English tries to do have a one to one match with the sounds, but there are many more sounds than there are letters in the alphabet. Depending on how you count, there are, at least, 13 vowels with only 5 characters to represent them.
Surprisingly, the most common vowel in English, schwa /ə/ doesn’t even have a letter to represent it so we use the upside down e. The letter i, is pronounced differently in bit, bite which is different than most other languages where it is pronounced like the ee in bee.
When linguists study language, we mostly study spoken language. One reason for that is relatively few languages have writing systems. But, when you are learning English, you need both. Most English words follow simple rules that allow you to figure out how to say a word or how to spell it. However, many don’t. I think of it like learning Chinese characters, you just have to memorize them. If a billion people can learn to do that, how hard could it be to memorize a few hundred words?