PurePos is an open-source HMM-based automatic morphological annotation tool. It can perform tagging and lemmatization at the same time, it is very fast to train, with the possibility of easy integration of symbolic rule-based components into the annotation process that can be used to boost the accuracy of the tool. The hybrid approach implemented in PurePos is especially beneficial in the case of rich morphology, highly detailed annotation schemes and if a small amount of training data is available. Evaluation of the tool was on a Hungarian corpus revealed that its hybrid components significantly improve overall annotation accuracy.

The tool is LGPL and is available on Github.