The reliance on third-party language packs often stems from frustration with official distribution. Players in America, for instance, have voiced concerns on the CD PROJEKT RED forums that they are sometimes restricted to specific audio options despite wanting other dubs, such as Castilian Spanish, which might be locked to European versions.
For those using official versions of the game, you can manage your language settings directly through the in-game menus or platform settings as shown here:
Localization was a massive undertaking for CD PROJEKT RED, as the game's script was originally written in before being translated into English and other languages. The official support for the game varies significantly by region: