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Open-plan offices were popularised partly on the promise of easier collaboration, yet acoustic research complicates that assumption. Speech is the most distracting type of office noise because the brain automatically parses language for meaning, making it far harder to ignore than mechanical hums or distant traffic. Studies using simulated office environments have found that a single nearby conversation can reduce a worker's short-term memory performance more than continuous background chatter from many overlapping voices, since overlapping speech becomes harder to isolate and interpret. This has led some architects to design offices with sound-masking systems that add a low, steady hiss to blur speech intelligibility across a room, rather than eliminating noise altogether. The goal is not silence, researchers note, but reducing the intelligibility of nearby speech to a level the brain no longer feels compelled to decode.