In 1990, Congress passed the Americans with Disabilities Act, which prohibits discrimination against individuals with disabilities in employment, public services, telecommunications, and public accommodations. The last part—“public accommodations”—includes concerts, so music venues are now required to provide American Sign Language interpreters for hearing-impaired audience members.

Some translators sign a song's lyrics and make the hand sign for “music” whenever an instrumental interlude occurs. But as the Vox video below explains, an increasing number of interpreters are using a new, specialized version of ASL to visually convey beats, bass and guitar riffs, complex hip-hop lyrics, and more.

Watch Amber Galloway Gallego—who’s interpreted for over 400 artists, including Adele, Drake, and The Cure—in action below.

[h/t Vox]