Should teachers be held to a higher level of accountability when it comes to grammar, spelling, etc.?

Man. I subbed in a 3rd grade class room the other day. As it turns out, the teacher was in the building, but at meetings or something. She left no lesson plans, and came flying in at 8:20 to scribble something out on a paper. Some of her comments were, “Well, this ain’t exactly what we’re doing but they seen it before.” And, “We was gonna do this, but we ain’t now.” And, on the board was written, “When your done with page 3, do XYZ.” Also, on the scribbled lesson plan was the ever wonderful, “Could of….”

As an aside, her room was a total, disorganized mess….but her grammar is what floored me the worst…...I can’t figure out how a person like that could be hired as a teacher.