One of the distinct advantages of free software is the diversity of the community, which often translates in a wider language support. This is the case of LibreOffice, which is able to support a larger number of languages than Microsoft Office (and of other open source office suites).
The table is based on information available online, about available language packs for LibreOffice, Microsoft Office, Apache OpenOffice and Calligra (which users can download to have at least the User Interface in their native language).
Numbers are native language speakers, according to the last version of Ethnologue (which is considered a reference from Wikipedia, and other sources as well).
If you find a mistake, please leave a comment and I will update the document as soon as possible. Any other comment to this post will be deleted.