Wikimedia Commons holds over fifty million freely-licensed media files. These millions of images, sounds, video, documents, three-dimensional files and more contain a vast amount of information related to the contents of the file and the the context for the world around them. As Commons has collected files over the years, the volunteers who curate and maintain the site have developed a system to contain and present this information to the world, using MediaWiki, wikitext, and templates.
A description template is the first and primary way information about a file is show to users. These templates can be a powerful tool for displaying information about files; descriptions provide meaningful context and information about the work presented. Descriptions can be as long as the user would like, providing wikitext markup and links for others to find out more. Description templates can also hold translations by adding language fields. However, the Structured Data team saw some areas that a feature like captions could improve upon from descriptions templates.
Multilingual captions help share the burden of descriptions by providing a space to describe a file in a way that is standard across all files, easy to translate, and easy to use. Captions do not support wikitext so there is no knowledge needed of how to links work in this space — links can still be provided in the more expansive file description. Captions are added during the upload process using the UploadWizard, or they can be added directly on any file page on Commons. The translation feature for captions is a simple interface that requires only a few steps to create and share a caption translation.
The “multilingual” in “multilingual captions” highlights a primary focus of Structured Data features: opening up access to Commons to as many languages as possible beyond its present capabilities. This is enormously beneficial to the Wikimedia movement and Wikimedia Foundations’ mission of sharing knowledge with the world. In addition to captions, future features planned provide supporting adding “statements” from Wikidata to files, effectively describing them in an organized way that can be accessed by programs and bots to present media. These statements can be multilingual as Wikidata supports translations, which will make statements searchable in any language that has a translation provided.