According to practically every grammar I've encountered, "I demanded them to leave" is incorrect English. I've quite literally spoken like this all my life; I don't know if it's a dialectal thing (I'm from the NYC area), or if it's simply an error of my own idiosyncratic speech. However, as someone who teaches English Language, I don't want to make any mistakes concerning my pupils' language acquisition. It's extremely important to me that I clarify this subject before I continue teaching it… I'm afraid to create a generation of poor English-speakers!
Does anyone else speak this way? Is
My mother is demanding I clean my room before I leave
My mother is demanding me to clean my room before I leave
vastly different? Is one simply incorrect?