  Wiktionary is a unique, peculiar, valuable and original resource for natural
language processing (NLP). The paper describes an open-source Wiktionary
parser: its architecture and requirements followed by a description of
Wiktionary features to be taken into account, some open problems of Wiktionary
and the parser. The current implementation of the parser extracts the
definitions, semantic relations, and translations from English and Russian
Wiktionaries. The paper's goal is to interest researchers (1) in using the
constructed machine-readable dictionary for different NLP tasks, (2) in
extending the software to parse 170 still unused Wiktionaries. The comparison
of a number and types of semantic relations, a number of definitions, and a
number of translations in the English Wiktionary and the Russian Wiktionary has
been carried out. It was found that the number of semantic relations in the
English Wiktionary is larger by 1.57 times than in Russian (157 and 100
thousands). But the Russian Wiktionary has more "rich" entries (with a big
number of semantic relations), e.g. the number of entries with three or more
semantic relations is larger by 1.63 times than in the English Wiktionary. Upon
comparison, it was found out the methodological shortcomings of the Wiktionary.
