Latency

The time delay between when an event occurs and when its accessible representation is delivered to the user. In real-time captioning, latency is the gap between spoken words and their appearance as text, typically measured in seconds. In screen readers and other assistive technologies, latency refers to the delay between user input and system feedback. Low latency is critical for accessibility because excessive delays can cause users to miss context, struggle to follow conversations, or lose synchronization between audio and visual content. Acceptable latency varies by use case—real-time captions ideally stay under 5 seconds, while screen reader feedback should be nearly instantaneous.