I did: in fact, until I looked "phonics" up just now, I had no idea that wasn't just the way that all native speakers learned to read.

Teaching language is often, like many other things in life, determined by fashion. It is quite fashionable in many English speaking countries to use phonics when teaching children, but it's not something that is done in 100% of schools, and it wasn't always done in the past. Personally, as far as I remember, I wasn't taught using a phonics approach and I didn't really learn to read until much later than most other children, but I believe this was because I wasn't interested in the simple stories in kids books. Once I discovered more exciting stories, I had the motivation to read, and that's what really helped me to learn how. I think every person is different but one of the criticisms of phonics approaches are that they don't always teach in context, and many people think learning in context is the best way. When we 'learn' a word it's not simply a case of seeing or hearing the word once, understanding (or translating) it. In fact we often need to see, hear, use a word many times (researchers think the average is about 10 times) before we really learn it. Please don't misunderstood me, there are a number of different books, websites, apps that can help you with a phonics based approach, but I just wanted to say "Relax, don't worry if you can't remember how to pronounce a word the second time you see it."

Yes, native English speakers learn phonics and it would probably be a good idea for you. I did an internet search for “English phonics for adults” and got a number of hits. You may have luck finding something online made for adults, if you look.

I don't remember exactly how I learned, but I can confirm that children are taught phonics right from nursery now. My mam told me she was taught to spell phonetically, which obviously wasn't good advice for English. Phonics is much better I think.

Yes. When English speaking children learn to read, they usually learn the spelling to sound (and sound to spelling) relationships using phonics. As there are 26 letters and 44 sounds, the spelling to sound relationship is somewhat complicated. Most pronunciation books (such as English Pronunciation Made Simple) have a brief review of the common spelling patterns for a given sound. Additionally, stress patterns change pronunciation. Unstressed vowels tend to be become "uh" or even disappear. "Today" >> "tuhday" >> "tday." Finally, some English learners have never learned the 44 sounds of English, and they rely on the sounds of their first language. As a result, they don't hear words correctly, they don't remember word pronunciations correctly, and they don't pronounce words correctly.