The env_sentence entity allows you to make announcements; think of the announcer in Black Mesa from Half-Life's single player mode.
Keyvalues
"Sentence", _text:
Put a space-separated list of WAV-file names from the "sounds/vox"-folder here, without the ".wav"-extension. Put a period for a pause, e.g. when at the end of a sentence. E.g. "unlocked maximum power.get out of hazard zone immediately".
Notes
The announcer is audible over the whole map, in full volume, with no stereo or 3D-audio effect in relation to the env_sentence's position.
This can be triggered repeatedly and cause the same sentence to be read out multiple times in one moment.
Unlike other entities, env_sentence sends the same output type as received, instead of 'Toggle'.
Flags
1: "Activator Only": Announcement will be heard only by player who is an activator of script (e.g. he pressed a button that triggers this entity).