  With the fantastic growth of Internet usage, information search in documents
of a special type called a "wiki page" that is written using a simple markup
language, has become an important problem. This paper describes the software
architectural model for indexing wiki texts in three languages (Russian,
English, and German) and the interaction between the software components (GATE,
Lemmatizer, and Synarcher). The inverted file index database was designed using
visual tool DBDesigner. The rules for parsing Wikipedia texts are illustrated
by examples. Two index databases of Russian Wikipedia (RW) and Simple English
Wikipedia (SEW) are built and compared. The size of RW is by order of magnitude
higher than SEW (number of words, lexemes), though the growth rate of number of
pages in SEW was found to be 14% higher than in Russian, and the rate of
acquisition of new words in SEW lexicon was 7% higher during a period of five
months (from September 2007 to February 2008). The Zipf's law was tested with
both Russian and Simple Wikipedias. The entire source code of the indexing
software and the generated index databases are freely available under GPL (GNU
General Public License).
