ParaMor: Finding Paradigms across Morphology. Workshop of Morpho Challenge 2007

ParaMor, our unsupervised morphology in-duction algorithm placed well in Morpho Challenge 2007 (Kurimo et al., 2007). Morpho Challenge is a peer operated com-petition pitting against one another algo-rithms designed to discover the morpho-logical structure of natural languages from nothing more than raw text. Of the four language tracks in Morpho Challenge 2007, we entered ParaMor in English and German. Morpho Challenge 2007 evalu-ated systems on their precision, recall, and balanced F1 at identifying morphological processes, whether those processes mark derivational morphology or inflectional features. In English, ParaMor’s balanced precision and recall outperform at F1 an al-ready sophisticated baseline induction al-gorithm, Morfessor (Creutz, 2006). Pa-raMor placed third in English overall, be-hind two algorithms both submitted by Delphine Bernhard. In German, ParaMor suffers from a low morpheme recall. But, combining ParaMor’s analyses with analy-ses from Morfessor, results in a set of analyses that outperform either algorithm alone, and that place first in F1 among all algorithms submitted to Morpho Challenge 2007.