>english is probably not correlated tightly with IQ as it is more affected by language background and education.

No, see: https://en.wikipedia.org/wiki/G_factor_(psychometrics) English and math has a 0.64 correlation.

I feel like it's a common misconception that IQ only tests some narrow intellectual abilities like math and logic, likely because online tests and fake IQ tests tend to focus on those kinds of puzzles. Actual IQ tests actually do place heavy emphasis on language skills like vocabulary, verbal abstraction and comprehension.