I dont disagree with the idea that the purpose of reading is to understand. My assertion is that lack of familiarity (or better said lack of seeing unless used

I dont disagree with the idea that the purpose of reading is to understand. My assertion is that lack of familiarity (or better said lack of seeing unless used often) is the cause of the hard to understand issue and not that unless is a word hard to understand on its own. Here is a question to reflect: How come ! is easy to understand while actually "not" is better (short enough to not consume reading speed while being explicit)? But a lot of languages are using ! so it seems to be good enough for reading. My answer to this is: because it is used so much => familiarity.