Right click and Save as... and put this file in %YOURSTEAMDIRECTORY%/steamapps/dota 2 beta/game/dota/resource/ (mine is D:\Steam\SteamApps\common\dota 2 beta\game\dota\resource) for dota 1 hero names in your dota.
Revert it by deleting the file and verifying cache or replace the new dota_english.txt with the one provided below. If you get broken strings like #DOTA_RP_INIT and stuff like that you need to do this.
Default dota_english.txt