Multi-language orgs can enable Lightning Knowledge, and Lightning Knowledge orgs can turn on enable multi-language support. Translated articles are searchable and readable in Lightning Knowledge. However, creation and management of translated articles is only available in Classic currently. In addition, users can add language as a column in the listviews. If there are published translated versions of an article, users can easily switch to another language when viewing the Article Record Home by using the language picklist. If a translation language only has a draft version, that language won't show in the picklist until it is published.