Volunteer community members have used our content translation tool to create over 300,000 articles, thereby spreading knowledge across language barriers. The tool has had already a positive impact in many Wikipedia communities, and now the Wikimedia Foundation's Language team is working on a new and improved version.
To celebrate International Women's Day and Women's History Month, Wikimedians around the world make a concerted effort each March to add and edit articles about women in Wikipedia. You can also have an impact (and fun!) by adding information about women to Wikidata, Wikimedia's multilingual knowledge base. And there are quite a few interesting and fun, volunteer-developed tools to help you with that.
Many of the languages of the world use two or more writing systems, like the familiar Arabic, Cyrillic, or Latin scripts. Supporting those languages and those scripts—for reading, editing, and searching—can be a real challenge.