From Dota 2 Wiki
For the default announcer, see Announcer responses.
Announcer items are cosmetic items replace the voice responses of the default announcer. They can equipped in the loadout window. Like HUD Skins, Announcers can be shared with team-mates through the Shared Content panel.
- Announcer Packs replace all lines, except for killing spree lines.
- Most custom announcer packs have more lines than the default announcer.
- Mega-Kills Packs replace killing spree lines.