I don't how the English evaluation works in the average (US?) school, or even what's in the exams. But it's possible to have useful native language exams with objective evaluation.

Until 2006, the national Finnish/Swedish (as a native language) exam at the end of high school in Finland consisted of two essays. One was based on materials that were provided, and another on a topic that was given. I believe there were a few options to choose from. Both essays were scored independently, and your score was the better of the two. If you had learned to write essays, it was effectively an intelligence test and a good predictor of future academic success across many fields.

Including CS, as my department found out. In particular, the ability to write essays was a better predictor of success in CS studies than the scores in mathematics and natural sciences. Probably because there has always been a large subset of CS students who are otherwise good at CS but can't handle anything resembling mathematics.