What cognitive skills and other factors (types of exposure, practice, knowledge of the language, etc.) affect one's ability to read aloud fluently in a foreign alphabet — or even in one's native language/alphabet? Are there any studies which show how these factors compare to each other in terms of their ability to influence reading speed and proficiency?
Background/motive for the question (Feel free to skip reading this!):
Example #1 from my own history:
I developed superior reading-aloud skills in my native language (English) very early in childhood; however, now, at age 27, I am no longer able to read aloud in English with anywhere close to the same fluency. I now have trouble reading long sentences with the correct cadence, which I never had as a child. I experienced certain cognitive insults in early adulthood which may go some way toward explaining this change, and I would like to learn how to remediate them if possible.
Example #2 from my own history:
I began a third language, Russian, in young adulthood. It was my first time learning a foreign alphabet. I began the process long before the cognitive insults occurred. All the same—and despite my success with English—I was extremely slow in learning to read Russian (Cyrillic) text out loud fluently. I was one of the slowest readers (and learners of this skill) in my class, despite normal to superior performance in other, measurable aspects of cognition, i.e., a perfect SAT score.
I had no problem reading a transliteration out loud, but when it came to text in the foreign alphabet, even years of studying Russian did not help me get faster. I only finally learned to read aloud fluently in Russian when my Russian itself was fluent; by then, I knew the words and their contexts well enough that I didn't have to process letters individually anymore, and could basically read by guessing.
Example #3 from my own history:
The next alphabet I learned to read aloud was Hebrew. Despite several years of daily practice, to this day, I am painfully slow at reading Hebrew aloud. I attribute this to the fact that I do not have even an elementary knowledge of the Hebrew language, and thus cannot recognize patterns nor predict words.
BUT, I am studying another language--Yiddish--with the same alphabet, and I am almost as slow at reading that, despite the fact that I have a solid basic proficiency in Yiddish, unlike Hebrew. My Yiddish reading is slightly faster than my Hebrew, but not by much, even though the difference between my Yiddish knowledge and my Hebrew knowledge is significant.
....From what cognitive shortcoming am I suffering?