My parents were born in Ethiopia so their first language was Amharic. In our childhood, my siblings and I learned to speak and understand the language via osmosis.
No one ever sat me down and said "this is what a flower is called" or "that is what a chair is called". You just absorb meanings, fill in the gaps, and become a fluent understander and a semi-fluent speaker.
In recent times I have dropped to a below-conversational level of speaking, partly due to my shyness of embarrassing myself around fluent speakers, and partly due to my non-use of the language since moving out for college.
Sometime in my mid-teenage years I was on a trip to Ethiopia with my family. I had been 6-7 times before as we often went to visit relatives. One thing that always piqued my curiosity when I visited was that I couldn't read street signs or billboard advertisements.
Any time we would visit, a relative would set us up with a dedicated driver named Temesgen (ተመስገን) who would drive us everywhere.
Over time, I befriended him and when my family would leave the car to do something, I would stay behind and we would just chat in broken sentences (his English, mine Amharic). This somehow worked well.
One day, I stayed behind and as we chatted I mentioned how I wish I could read and write Amharic. He paused and reached into the center compartment and came out with a book.
He said, "I was thinking about this and got this for you". It was a children's book for learning to write Amharic (whose letters come from a variant of Ge'ez script).
I flipped through the pages, my fascination was fully captured. It became my mission to make sense of these cryptic symbols so I could finally understand these meaningless signs I kept seeing.
Temesgen said, "next time you visit, I want you to come back reading books back to me". I tucked the book in my backpack, I was leaving back home shortly.
When back home in Maryland, I started working through the book.
For the next two weeks, my parents found me pencil in hand, repeatedly writing down symbol after symbol in this children's book. My parents became curious about what I was doing and I explained to them that Temesgen had given me this book. Surprised, they remarked how that was nice of him.
I came into it with no formal teacher, a clean slate. A few pages in, I realized a key pattern.
The key to learning 80-90% of the alphabet was to learn the base sound symbols (the base consonants), then how the "add-on" sounds visually changed the form of the base sound (this was not always consistent).
Other anomalous forms of symbols that "broke" any visual pattern could be patched over as "one-offs" and just internalized over time.
Aside: More technically, each sound is a consonant-vowel combination, we want to pattern match how the first symbol changes when our root consonant phoneme is joined with different vowels. At the time I had no awareness of linguistic principles that could have aided me in my pattern matching.
Off of each root consonant, there are 7 derived sounds. Above, in the first row, we have the sounds "ruh", "roo", "ree", "rah", "ray", "ruu", "ro" (I will avoid using IPA, they are pronounced as naturally read). In the second row, we have "suh", "soo", "see", "sah", "say", "suu", "so".
I noticed some patterns for the suffix variants:
"-uh": base symbol, we just have to memorize these
"-oo": a mid-dash off the first symbol
"-ee": a base-dash at the bottom of the base symbol
"-ah": a left-side "truncation" of the base symbol
"-ay": a "bay of water" loop would appear somewhere, often lower-right on the base symbol
"-uu": there was a "bending" somewhere, often at the top of the base symbol, sometimes the symbol completely transformed into a similar-looking variant
"-o": a right-side "truncation" of the base symbol, sometimes our "bay of water" loop would appear higher up on the base symbol
Taking into account the above rules we can look at some more symbols and see if they hold.
The rules were generally accurate.
Aside: Of course, when a native speaker is reading these symbols, they are not running an interpreter thread in their minds to decode each letter, then the meaning of whole words. It just all comes together in a split second.
When I observe my father read, he would make sense of words as a whole image, his neural network trained on hundreds of thousands of input combinations. It was all one block of meaning to his trained mind.
The method of piece-by-piece interpretation was slow, but it was consistent & accurate.
After the 2 weeks of studying, I felt like my interpreter had reached a solid point.
On the last day of my studying, I walked into the living room where my parents were watching Ethiopian television. They were watching the news - the word "news" is pronounced "zay-na" (ዜና).
I walked behind them and read aloud, "Ethiopia's News" (የኢትዮጵያ ዜና) in Amharic.
My mom slowly turned around, shocked, and said "I didn't know you could read."