You're reading. A book, an article, this note. You reach the bottom of a paragraph. You have no idea what it said.

So you go back. Read it again. Get to the bottom. Nothing.

Again. Nothing. The words enter your eyes and exit through the back of your skull without touching anything on the way through.

What's happening: Your eyes are processing the text, but your working memory is occupied. Something else has the buffer (a background worry, an unresolved task, a thought that won't release its hold on cognitive resources).

Reading comprehension requires simultaneously decoding words AND integrating them with context AND holding the accumulating meaning AND connecting to prior knowledge. That's four working memory operations at once.

If even one background process is consuming working memory (and for you, one always is), there isn't enough headroom for all four operations. So you decode without integrating. The words are processed but not comprehended.

You're not stupid. You're not illiterate. You're trying to run a program that requires more RAM than you currently have available.

Close some background processes first. Then read.