Some people hardly notice nor that they are using the idiom, so sometimes when we communicate with foreigners, we may be confusing because it does not understand the meaning of the speech outline.
Some people do not even know they're using the idiom, so sometimes when we communicate with foreigners, we may be confusing because it did not understand what they say.
Some people don't even think he was using idiom so sometimes when we communicate with foreigners, we may confuse you don't understand meaning has he said.