rish3 - 1:35 pm on Jun 14, 2013 (gmt 0)
The 'language filter' works by detecting bad grammar or usage, rather than focusing on quality. (Fair enough)
I suspect that it has nothing to do with bad grammar. It's probably just the Fleisch-Kincaid reading level formula. You can check wikipedia for details, but it boils down to how many words in a sentence, and how many syllables per word.
You can get some pretty awful copy to show up as "Advanced" simply by creating run on sentences with lots of long, multi-syllable words. Advanced does not necessarily imply "Good", and "Basic" does not imply "Bad".