Personally, having people around, hearing speech (and involuntarily passively processing that speech), on top of environmental noises, is utterly distracting and hinders any kind of productivity.

While I'm working, preferably alone, ear buds are in and a long instrumental track is played on loop, so that noise is drowned out, don't get distracted by having to select another song, and there's no need for my brain to process speech. It's amazing how well it works in keeping me focused.

As of late, been playing Autechre's "Bike"