We describe the system built by the National Research Council Canada for the "Discriminating between similar languages" (DSL) shared task. Our system uses various statistical classifiers and makes predictions based on a two-stage process: we first predict the language group, then discriminate between languages or variants within the group. Language groups are predicted using a generative classifier with 99.99% accuracy on the five target groups. Within each group (except English), we use a voting combination of discriminative classifiers trained on a variety of feature spaces, achieving an average accuracy of 95.71%, with per-group accuracy between 90.95% and 100% depending on the group. This approach turns out to reach the best performance among all systems submitted to the open and closed tasks.
Both systems used a two-layer classification, comparable to REF : the first layer identified the language group, the second layer trained multiple classifiers to identify language varieties within the groups.
The NRC System for Discriminating Similar Languages
VarDial@COLING
Computer Science