If you don't understand, start walking further away from the cities.

If you still don't understand, you're not done walking.

So I am a researcher by trade in this field, got a PhD, and develop these kinds of stats (at a more local level). I also have taught basic adult literacy for about 15 years. I think the poster was likely referring to an NCES stat.

We tend to think of adults with low English literacy as people who dropped out of school or never went. We also tend to think "illiterate" is binary, you can read or you can't. But the definition is based around grade-level reading (what can you identify and synthesize from standardized text in English in a given time frame) and inclusive of a broader population. We're talking about people who can't pick up a copy of USA today and tell you the main idea of a front-page article. They can drive, they can work, etc. So they get along and this issue get ignored.

For example, some stats on illiteracy will count "non-participants" among those who can't read/write, but this includes people in the study with cognitive disabilities or language barriers to the point that they can't take the reading test. The share of U.S. adults who are functionally illiterate in English includes some non-native English speaking adults and also a couple generations of folks with reading diasbilities who passed through school, AND people who didn't read for myriad other reasons.

I have tutored older adults learning to read/write for many years and have met a lot of people who ran businesses or raised families or worked full careers before learning to read. Adaptable and clever bunch. And even many U.S.-born native English speakers who got shuffled through high school despite serious disadvantage and/or disabilities.

Because the government, federal and state level (especially conservative) hate public education and fight to defund it as much as possible. Largely because an educated populace is a dangerous populace. Especially when your political platform relies on identity politics, culture wars, cheating, screwing over the poor, opposing minorities, religious fundamentalism, and any other regressive, oppressive bullshit you can think of. They want stupid voters that they can point at "the enemy" and pit against each other to distract them from facts, all so they can stay rich and powerful.

No single answer is comprehensive enough to explain the low literacy levels in the US. That’s because some of the contributing factors include:

• Parents with little schooling.
• Lack of books and reading encouragement at home.
• Dropping out of school.
• Difficult living conditions – including poverty.
• Learning disabilities.

Each of these topics has social and political implications and we, as a society, have made choices that privilege the rich and the least vulnerable. Our immediacy leads us to focus on inflation rates, employment, and reelection (don’t get me wrong, these are essential points). But we should also seek solutions to bring parents back to school, campaign for more books at home, and improve schooling to prevent dropout.

The discussion of U.S. illiteracy gets gloomier when we consider the differences between “literacy” (reading, writing, and math skills) and “functional literacy” (the practical use of these skills to manage daily life and improve socioeconomic well-being).

There’s a long and rocky road to reverse this picture, and some of the possible solutions to promote higher levels of literacy in society should take into account:

• low income resources
• stigma and shame
• lack of awareness
• limited access to education
• technological barriers
• limited funding for literacy programs.

So, how is it possible that roughly 50% of Americans can’t read above a 6th grade level and how are 21% just flat out illiterate?

All of the above, and probably more!

Part of the reason so many can’t read above a 6th grade level is that they are always written to on that level. Anything written for any commercial purpose is always written at a low level so any idiot can understand the menu / read the packaging / consume the magazine ad / whatever. Commercial writers write for the lowest common denominator and to an extent, news media do as well.

So a 6th grade reading level is really all you need to get by. Unless you actually read books or opt for The Economist or something else that doesn’t assume you’re a moron, 6th grade level is all you’re gonna see.

There’s some utility in this. Simpler language is also lowest-common denominator for second-language-speakers, of which we have many. Another reason to use it.

This disaster did not come about by accident. The whole country has allowed our public schools to decline, but the conservatives have been actively working to destroy them since the 80's. They have been leveraging racism, fundamentalism, and other prejudice-based fears to undermine the curriculum. Meanwhile, they have cut school funding, made teaching a terrible job, and downplayed the value of formal education. Educated people are much harder to manipulate. A minority trying to hold onto power needs a public that is poorly educated and without critical thinking skills.

I’m not an expert, but I have to imagine it’s in relation to the fact that public education in the United States tends to be rather underfunded. Teachers often don’t have all the resources to do their jobs effectively, and many resort to paying for resources out of their own pocket.

Pair that with the fact that the average salary for a teacher in a public school is almost criminally low for a position that has a massive impact on our social outcomes, and you get students that are disengaged and overall not as prepared as they could be.

This is all just what I’ve gathered from reading news articles over time. I’m sure there are several other factors at play.

As a school psychologist who completes academic assessments when identifying students with learning disabilities, COVID skyrocketed these numbers. There's just not a lot of motivation for kids anymore. The future is here and is making our population slowly illiterate.

Republicans.

One small part of the problem I only learned about recently is the Whole Language approach to teaching reading. Basically teaching kids to guess what words make sense instead of actually teaching them how to read. It was popularized in the 80s and 90s but continued to be used in some parts of the US into the 2010s. An entire chunk of the US population (and a few other countries as well) was literally not taught phonics/sounding it out because their teachers or schools followed this ineffective alternative method.

Of course that's far from the only factor, but it's one many aren't aware of.

My girlfriend is a math teacher, the number of middle schoolers that can’t do basic multiplication before is surprisingly high. Yet the schools keep passing the kids. I remember learning multiplication as a 4th grader, if I hadn’t, I would’ve never passed.

Everyone is very focused on recent history. What about the huge amounts of aging immigrants in the USA that migrated here for a better life in the 50s-70s from poor countries and no education? They just worked their ass off and reading wasn't a priority. My father was a poor shepard, no education and illiterate but he hustled and retired early and put me through college to be an engineer. It seems improbable but it is possible for someone to be illiterate and wildly successful and contribute a lot to society and culture.

If you want to know the truth, it's because America prioritizes almost everything above education in the money department. And while I enjoy making sure that Putin can't take over countries do to America's astronomically large defense budget, and help from other countries, we could probably use some of that money to help education, but you can't do that because what is cheaper/free college going to do for the military? That's right, cut in to the people who go to the military for free/cheap education. there's more to it but that's the gist, is that military eats up most of the federal spending, and then what trickles down to states, counties, and cities, is done as those people see fit. Some schools, cities and counties do well, but Michigan, and the south really aren't helping things, plus you have teachers paid poorly, who may of had a love for teaching, be stressed out all year around, and they may tell that kid who is an annoyance in class that he can have the easy book because they won't shut up and bring a nuisance, to let them read some small chapter book or something for a report than not. I've seen it happen plenty when I was in high school. But it boils down to money mostly.

Schools cannot force students to learn. A lot of people are having kids because of social/societal expectations, lack of sex education, or lack of access to birth control rather than because they actually want to. As a result they are much less involved in their childrens' lives and expect schools to take care of raising their children for them. Stagnating wages and rising cost of living from inflation or corporate greed or whatever you want to call it means that even parents who do care are often too busy trying to make ends meet to be active parents. I suspect all of the above factors also correlate to parents who are not very well educated themselves.

If kids do badly, rather than encouraging or incentivizing them to do well or addressing their behavioral issues, these parents will instead blame the teachers. It is getting to the point where this is the case for the majority of students in many places. I have friends who teach in selective private schools, which would in theory correlate to more resources for students and more involved parents, but even there they are starting to see this.

Schools don't have the resources to address this crisis properly; schools are funded by tax dollars so teacher pay and overall school funding have stagnated along with wages. Schools cannot fail every student or hold them back a grade, and they are also incentivized to have high average grades, so they end up lowering their standards and graduating students who are not properly educated.

My personal, cynical take on this is that a subset of people in positions of political power realize that uneducated people are easier to manipulate for their own gain, and therefore deliberately support policies that have lead to the deterioration of educational standards. Additionally, business profits are maximized, at least in the short term, by maximizing the number of people living on the brink of bankruptcy. Every cent that the average person saves or invests or passes on to their children is a cent that is not being added to the billionaires' hoards. Less educated people are easier to manipulate into voting politicians who allow this to happen into power, which gives large corporations an incentive to help the aforementioned politicians get elected.

Income disparity, communities where education isn’t supported, underfunded education, book burnings, tv/internet/gaming they've all had an impact. Add covid to the mix and burnt out parents and it’s all coming to a head

The Every Student Succeeds Act, which is the successor to the No Child Left Behind Act, puts the accountability for education in the hands of individual states rather than the federal government.

Journalist Libby Nelson wrote that the ESSA was a victory for conservatives who wished to see federal control of school accountability transferred to states, and that states "could scale back their efforts to improve schools for poor and minority children".

The overall effect is that education standards are lowered so that low-performing students can "succeed" (receive a passing grade) without being forced to actually learn.

And later the accountability requirements for states were removed:

In March 2017, Republican lawmakers with the support of the Trump administration used the Congressional Review Act to eliminate the Obama administration's accountability regulations.

So the real answer to your question is because Republicans are stupid and shortsighted and they want to keep the general population uneducated so they can be more easily manipulated.

The republican right wing has been de-funding public schools and decrying all education as leftist indoctrination for about 50 years.
Actions have consequences, or in this case, results.

As a non-native English speaker, suddenly I feel more proud of myself.

Because you have a deleterious government that has purposefully de-prioritised education in order to command greater control over a brainwashed population.

Same everywhere. I think 53% of people in Quebec are functional illiterate. There is an article today about French students being illiterates too.

The educational system wants this. I start to think it's by design.

Think about what kids read in 6th grade - Call of the wild, Holes, Black Beauty, etc. Then look at the grammar of people who post here. I was taught that basic newspapers are written at a 3rd-4th grade level.

Because they "love the poorly educated"

/s

edit:typo