Drawing from this raw data posted in the comments
- 21% of West Virginians are at or below Level 1 PIAAC competency, the ability to "locate a single piece of information that is identical to or synonymous with the information given in the question or directive" in English. 28% of Californians, 24% of New Yorkers, and 21% of New Jerseyans are at or below this rate.
- 37% of West Virginians are at or above Level 3 PIAAC competency, which includes the ability to "identify, interpret, or evaluate" "rhetorical structures". 46% of Californians, 44% of New Yorkers, and 47% of New Jerseyans are at or above this rate.
On average, West Virginia appears to have fewer people with very low literacy than the coastal states, but also fewer people with very high literacy. The latter figure is a larger figure so this will push West Virginia towards the back of the pack in ranking overall literacy skills, although it may indeed have fewer people who are completely illiterate in English.
The government agency that does the counting ranks West Virginia in the bottom 25% states for average combined English literacy and numeracy skills... alongside California and New York. Most of the states in the top 25% are bordering Canada, and nearly all of the worst 10 counties are Texas counties bordering Mexico.
Since this answer might serve to validate some people's stereotypes about West Virginia, I would also like to examine the logic of Bette Midler's tweet, which refers to West Virginia as poor and illiterate on the watch of Joe Manchin. The assumptions here appear to be that poverty and illiteracy accompany ignorance, and that West Virginians vote for Joe Manchin because they are ignorant, and that he keeps them that way. These assumptions appear fallacious (and mean, and stupid) on first glance and certainly merit critical thought.