This comment explains why user-testing requirements for accessibility are necessary for usable advanced communications services or products. Written in conjunction with Professor Clayton Lewis of CU-Boulder’s Coleman Institute, the TLPC’s comment explains why user-testing best serves the purposes of the Twenty-First Century Communications and Video Accessibility Act. The comment additionally explains how the Act applies to people with cognitive disabilities and, moreover, analyzes how the Act may be defined to the full extent that Congress intended. This interpretation ensures that people with disabilities have full access to advanced communications technologies. The comment proposes a complaint-based enforcement process that will help implement reasonable user-testing requirements for accessibility.