ELAN is a professional tool for the creation of complex annotations on video and audio resources. It enables linguistic analysis to be timelinked to video. With ELAN a user can add an unlimited number of annotations to audio and/or video streams. An annotation can be a sentence, word or gloss, a comment, translation or a description of any feature observed in the media. Annotations can be created on multiple layers, called tiers. Tiers can be hierarchically interconnected. An annotation can either be time-aligned to the media or it can refer to other existing annotations. ELAN provides several different views on the annotations; each view is connected and synchronized to the media playhead. ELAN is an essential tool for sign language linguistics research.