Simple pre-defined voice overs that may or may not be actual commands. Commonly exist in place of or as supplementary to text chat, voice chat, and text macros.
Alternate name: Voice commands
The first video game about Voice macros was released in 2005.
There's usually a few dozen different voice macros accessed whether by individual shortcuts or through a voice menu.
These can be something like "Yes", "No", "Medic!", "Help!", "Out of ammo!", and so forth, but commonly share the same short format. Some may be context sensitive, such as "Look!", which when pointed at something specific might produce more specific voice over, for example "Ammo here!", or generic "Look out!" which turns into shout warning about specific enemy, naming it and so forth.
Considering the voice overs are placed in 3D space like all other voices, and are easier to access in panic situation, they give greater sense of where the thing is as well as who used the command. Regular textual chat easily is too slow, tends to convey little locational info and whatever else, while voice chat suffers from quality of the speaker's microphone, the clarity of their speech, and their ability to convey as much information as possible in short message and not to forget the lossy audio codec used to transmit over the internet all contribute to the message not being received properly.