I’m moderately dyslexic and have some form of auditory processing disorder and the pop-culture descriptions of dyslexia as “oh, I see letters backwards” make me crazy. That sounds way more interesting, kinda neat, and something that one could more readily learn to deal with.
My experience is more like I see the letters looking just fine and normal if I just look at them, but as soon as I try to read them, which involves processing them in a line one-by-one, my brain loses track of what order the ones I just looked at were in and which way they were facing. And nevermind that a “B” only ever faces the one way; remembering which direction something is oriented in is like trying to remember a name that just won’t stick. (Most people have something obvious, like a name or small task, that they just cannot remember, right? For me, if a “three” looks like 3 or E is kinda like that.) This made learning phonics TOUGH, since it was an obvious obstacle to recognizing common letter groupings.
Phonics was made even harder by my having similar issues when I hear people speak. If I don’t have the context of watching someone speak, or really obvious related imagery, the various sounds of speech start to suffer a similar can’t-keep-the-order-straight block. It’s much milder than my more classic dyslexia and I do seem to have an easier time with people whose speech patterns I’ve learned and words in certain contexts. (If I’m staring at a computer screen, and someone on the phone tells me “start FireFox and then go to Gmail”, I’ll probably get what they’re saying just fine. If I’m on the phone and someone starts telling me a story about their day, I’m going to mishear, misinterpret, or just not get maybe ten percent of what they say. Which doesn’t sound like much, but in a classroom when I can’t watch the professor speak, it’s awful. Likewise, audio books and podcasts aren’t all that appealing to me.)
Luckily, I demanded to be taught to read fairly young, and perhaps my parents had patience because I was being precocious. I ended up enjoying books enough that I pushed through the difficulties and ended up testing well above my grade level in reading throughout school, however, to this day writing, especially by hand, is a struggle. I was put through years of remedial handwriting courses, none of which ever improved things. (Typing, for whatever reason, is much easier, but I know I backspace and correct much more than most do.) What’s most frustrating is it’s the actual act of writing the words-- translating them into the right string of letters in the right order and creating the corresponding shapes all facing the right way --that’s a struggle; composing them is something I enjoy and don’t believe I have too much trouble with. (Though I’d be embarassed to admit how long typing this post out is taking me!) Both issues have improved substantially as I’ve gotten older, which may have something to do with brain maturation or just practice at compensating. I can jot a legible note now, (and have even been told I have nice handwriting-- if I do, it’s because I’m having to draw each letter individually and very very carefully!) and have only had to take minimal steps to compensate now that I’m finally attending college. (I’m in my late 20s. I feel old.) But it affected my early education severely, and for many, if one’s childhood schooling goes extremely off track, it’s extremely difficult to ever overcome the results.
So, to bring this around to the OP, I certainly see how a dyslexic who had some accompanying auditory issues like my own would have a hard time memorizing dialogue, and why they might use the pat “I write upside down and backwards” descriptor, even though that’s not quite it and I feel it’s harmfully misleading.