I know a few words simply from my mother using them when I was in trouble as a child, but if you'd ask me some off the top of my head, I couldn't tell you (it was more of a context thing). My Grandparents on both sides of the family spoke it fluently.
My Grandfather's parents on my dad's side came over from Moravia in 1898 and immigrated through Galveston. I haven't finished researching my Grandmother's family on my dad's side, but from what I can tell, they came over much earlier, around 1846. From what I've found in an old family bible, the families suffered quite a bit at the hands of the KKK (anti-Catholic, anti-immigrant). They didn't understand the concept of slavery as they were brought up in a country where multi-generational families ran farms, so they didn't participate for either side during the Civil War. They had crops burned, a barn burned with livestock inside, and a Great Great Great Uncle was hanged. But I'm not sure if the Great Great Great Uncle was hanged by the KKK or if he committed a crime. There just isn't any records that I can find.
It is a real pain trying to read the handwriting that is in Czech and using Google Translate.