Unsupervised Morpheme Analysis with Allomorfessor

  • Sami Virpioja
  • Oskar Kohonen
  • Krista Lagus
Part of the Lecture Notes in Computer Science book series (LNCS, volume 6241)


Allomorfessor extends the unsupervised morpheme segmentation method Morfessor to account for the linguistic phenomenon of allomorphy, where one morpheme has several different surface forms. The method discovers common base forms for allomorphs from an unannotated corpus by finding small modifications, called mutations, for them. Using Maximum a Posteriori estimation, the model is able to decide the amount and types of the mutations needed for the particular language. In Morpho Challenge 2009 evaluations, the effect of the mutations was discovered to be rather small. However, Allomorfessor performed generally well, achieving the best results for English in the linguistic evaluation, and being in the top three in the application evaluations for all languages.


Machine Translation Mean Average Precision Word Form Mean Average Precision Viterbi Algorithm 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  • Sami Virpioja
    • 1
  • Oskar Kohonen
    • 1
  • Krista Lagus
    • 1
  1. 1.Adaptive Informatics Research CentreAalto University School of Science and TechnologyFinland

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