I'd recommend aiming for participation in the North American Computational Linguistics Olympiad and the International Olympiad in Linguistics. More information, including past problems, here:
<
http://www.naclo.cs.cmu.edu
/>
<
http://iol6.linguistics-bg.com/index.php
>
Best,
Brett
<
http://english-jack.blogspot.com
>
-----------------------
Brett Reynolds
English Language Centre
Humber College Institute of Technology and Advanced Learning
Toronto, Ontario, Canada
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