I actually see this ("could of" and "would of") more in native speakers than non-native speakers actually. I have also seen it used many times in writing so it'

I actually see this ("could of" and "would of") more in native speakers than non-native speakers actually. I have also seen it used many times in writing so it's not just a "heard it wrong" issue. Here in the South (US), it's disturbingly common.