Umm...I don't know what Tomb Raider games you were playing. She was never silent in the Tomb Raider 1 through Last Revelation that I played.
Guess I was just comparing it to that gameplay trailer where she doesn't shut up. The only times she spoke really were to say "Aha" when picking up an item, or during some of the cutscenes. Of course the occasional "uh" when falling.