Techniques described herein provide modifications to a communication session based on a proximity context. Various implementations establish a communication session between a local communication device and a remote communication device. In response to establishing the communication session, one or more implementations determine a proximity context associated with an area around the local device, such as by detecting a proximity of various objects to the local device. Upon determining the proximity context, various embodiments alter various operating parameters associated the communication session, such as by reducing a speaker volume and/or announcing the presence of a person within proximity to the local device.