This shit happened to me, but in kindergarten. I grew up in a bilingual house. I spoke English and Spanish equally. I went to the school with my mom to get assessed. She said I could read and was bilingual. The teacher didn't believe it and made me read from one of their books.
To add insult to injury, when they had Spanish class, the fucking teacher taught us that "purple" was "porpuda" and "lizard" wad "lizardo." Shit like that... My mom put me in another school.
I'm 48 and still laugh about lizardo. How absolutely stupid.