1. A computer implemented method of information retrieval, comprising: parsing a corpus to identify a number of wordform instances within each document of the corpus; generating a morpheme-by-document matrix based at least in part on the number of wordform instances within each document of the corpus, wherein the morpheme-by-document matrix separately enumerates instances of stems and affixes; applying a weighting function to attribute-values within the morpheme-by-document matrix to generate a weighted morpheme-by-document matrix; and generating at least one lower rank approximation matrix by factorizing the weighted morpheme-by-document matrix; and retrieving information with reference to the at least one lower rank approximation matrix.