We're happy to announce that after numerous tests and analyses[1] and a fully operational demo[2], the Discovery Team is ready to release TextCat[3] into production on wiki.

What is TextCat? It detects the language that the search query was written in which allows us to look for results on a different wiki. TextCat is a language detection library based on n-grams[4]. During a search, TextCat will only kick in when the following three things occur:

1. fewer than 3 results are returned from the query on the current wiki

2. language detection is successful (meaning that TextCat is reasonably certain what language the query is in, and that it is different from the language of the current wiki)

3. the other wiki (in the detected language) has results

Our analysis of the A/B test[5] (for English, French, Spanish, Italian and German Wikipedia's) showed that:

"...The test groups not only had a substantially lower zero results rate (57% in control group vs 46% in the two test groups), but they had a higher clickthrough rate (44% in the control group vs 49-50% in the two test groups), indicating that we may be providing users with relevant results that they would not have gotten otherwise."

This update will be scheduled for production release during the week of July 25, 2016 on the following Wikipedia's:

English [6]
German [7]
Spanish [8]
Italian [9]
French [10]

TextCat will then be added to this next group of Wikipedia's at a later date:

Portugese[11]
Russian[12]
Japanese[13]

This is a huge step forward in creating a search mechanism that is able to detect - with a high level of accuracy - the language that was used and produce results in that language. Another forward-looking aspect of TextCat is investigating a confidence measuring algorithm[14], to ensure that the language detection results are the best they can be.

We will also be doing more[15] A/B tests using TextCat on non Wikipedia sites, such as Wikibooks and Wikivoyage. These new tests will give us insight into whether applying the same language detection configuration across projects would be helpful.

Please let us know if you have any questions or concerns, on the TextCat discussion page[16]. Also, for screenshots of what this update will look like, please see this one[17] showing an existing search typed in on enwiki in Russian "первым экспериментом" and this one[18] for showing what it will look like once TextCat is in production on enwiki.

Thanks!

[1] https://phabricator.wikimedia.org/T118278

[2] https://tools.wmflabs.org/textcatdemo/

[3] https://www.mediawiki.org/wiki/TextCat

[4] https://en.wikipedia.org/wiki/N-gram

[5] https://commons.wikimedia.org/wiki/File:Report_on_Cirrus_Search_TextCat_AB_Test_-_Language_Detection_on_English,_French,_Spanish,_Italian,_and_German_Wikipedias.pdf

[6] https://en.wikipedia.org/

[7] https://de.wikipedia.org/

[8] https://es.wikipedia.org/

[9] https://it.wikipedia.org/

[10] https://fr.wikipedia.org/

[11] https://pt.wikipedia.org/