The Sindarin language pack included with the Precious Edition of The Lord of the Rings: Gollum only affects background characters and has no effect on the main story.
In a little over a month, the stealth adventure The Lord of the Rings: Gollum will be released. In addition to the basic version, the Precious Edition is a special edition with additional content. Said content includes a Sinadarin voice pack that provides Elvish voice acting for some characters.
As developer Daedalic now in a statement to press square explained, the language pack is only used for background characters and NPCs and only serves as a small atmosphere bonus for die-hard Tolkien fans.
In addition, there may be situations during the main story where certain characters speak Elvish without requiring the DLC:
“The Sindarin language pack adds additional Sindarin lines to some characters in the background. When Gollum travels through Mirkwood and other parts of Middle-earth he will be able to hear various dialogues between Elves. These dialogues add to the atmosphere and world-building.”
“Daedalic went the extra mile here, hiring professional voice actors trained in Sindarin by our lore experts. It’s a DLC for true Tolkien fans who want to delve even further into the world of Middle-earth.”
The Lord of the Rings: Gollum will be released on May 25, 2023 for Xbox Series X|S, Xbox One, PlayStation 5, PlayStation 4 and PC. A version for Nintendo Switch will be released at a later date.