"mi duck"

Posted by Pdianek on January 24, 2004

From SheffieldToday.net: One asylum seeker from Syria [said] . . . "I think Sheffield people are very friendly and have helped me feel at home. I have learnt to say 'mi duck' and now I support Sheffield United".

I'm supposing that "mi" is pronounced "mee" or a fast M-apostrophe. Why "duck"? Is this a particular-to-Sheffield expression? Meaning?