I used logic to demonstrate my side, while you simply just copy pasted links.
You used BS to demonstrate your side.
Alrighty. So, poor grammar is not necessarily related to intelligence level or education level. Often, people have learning disabilities that affect their ability to read and/or write effectively. You should know that according to the Individuals with Disabilities Education Act (IDEA), which is the federal law that governs special education practices in this country, a learning disability exists when academic achievement in a certain area does not meet expected criteria. One way to establish this is to note a difference between the child's intellectual ability and their actual achievement. This implies that learning disabilities are not related to intelligence level. In fact, there are people who have documented IQ's in the Superior range (above 130) who also have documented learning disabilities. Therefore, poor grammar is not necessarily related to intelligence.
Also, poor instruction can lead to underdeveloped grammar skills. In many urban school districts, there is not enough funding to be able to afford teachers who are capable of dealing with urban populations and overcrowding, and who are also willing to work in that type of environment. Because of this lack of funding, districts often have to hire teachers who are not able to handle situations, or are not emotionally invested in their job or students. This leads to poor instruction. Children pass from grade to grade without developing basic skills not because they are stupid, but because they are unfortunate enough to live within a district that cannot afford to provide them with proper and adequate instruction.
Furthermore, people who come to this country from other countries have the added burden of needing to learn an entirely new langage in order to function. These people experience very different home and school lives. Children go to school where they are expected to speak exclusively English. When they go home, they are expected to speak exclusively their native language. One problem that arises if the child is particularly young is that they have not yet mastered their own language when they begin to learn English. Research has clearly shown that it is necessary to develop mastery of your own language before you can master a second language, unless you begin learning both languages simultaneously. Research suggests that it takes between 5-7 years to master a language. If you consider that children generally start talking at around age 2, you cannot really expect them to master their own language until age 9 or so. If that child enters a school system before they have mastered their first language, they may end up having difficulty learning either language. Again, that has nothing to do with the intelligence of the child, nor does it necessarily have anything to do, ultimately, with the education level of the child. He/she could continue to progress through school without developing true mastery of spelling, grammar, etc. There are many people who are socially fluent in two languages or more who do not speak any of their languages with perfect grammar. That is one of the side effects of learning multiple languages with different sets of rules. I would say that a person who knows more than one language, but who speaks all of them imperfectly is better off than a person who only speaks one language with perfection.
There. How is that?