We parsed the wikitext of all files in Commons xml data dumps of November 20, 2017, and extract the language templates in them (e.g. {{en}}, {{LangSwitch}}). Out of the total 43,268,565 files, 14,848,551 (34.32%) files don't have any language templates, 23,780,247 (54.96%) files use only 1 language.

40.1% of all files have English templates, 9.38% of files use German, and 6.2% of files have description in languages which are not in the top 20.

For those files without language template, we use the langdetect package to detect their languages. We cannot detect any language in 556,684 files (1.29% of all 43,268,565 files). We detect 1 language for 7,577,789 (17.51%) files.

We detect English in 30.25% of all 43,268,565 files, detect German in 3.93% of files.

Results and analysis codebase: https://github.com/wikimedia-research/SDoC-Initial-Metrics/tree/master/T177358-1

Search query language breakdown note & results at https://github.com/wikimedia-research/SDoC-Initial-Metrics/tree/master/T177358-2