Lemmatization of the DIA1900 Diachronic Corpus

This paper focuses on the process of lemmatization of the upcoming Czech diachronic corpus of the second half of the 19^th century, DIA1900. The article describes different approaches to the corpus lemmatization of synchronic written, spoken and diachronic corpora within the Czech National Corpus project, including single- and multilevel lemmatization and available tools used to link the variants.