ELAN

A free, open-source annotation tool developed at the Max Planck Institute for Psycholinguistics for creating, editing, and searching multi-tier, time-aligned annotations on video and audio recordings. ELAN has become the de-facto standard tool for sign-language corpus work because it allows annotators to align multiple tiers — one hand, the other hand, mouth, eye gaze, head tilt, sentence boundaries, glosses — against a single video timeline. It is also used more broadly in spoken-language linguistics, gesture research, and multimodal interaction studies. For accessibility research, ELAN is the tool most commonly used to annotate sign-language corpora that train signing-avatar systems, sign-language recognition models, and interpretation research.