I donít know why a British linguist uses the Present Perfect with the time word- yesterday. Am I totally wrong to say that "Please teacher, I have heard this yesterday from a native speaker of English," is grammatical, please?
David Crystal was quoting a non-native learner when he used those words. He would almost certainly not use the words in his own speech, and he would not claim that they were correct.
Last edited by bhaisahab; 26-Oct-2013 at 22:18.
If he did, it would be one of those slips we make when speaking.