Please note: all credit goes to 451 Observant Sky !
How to reduce your install size of 8 Gb by removing optional files!
So, while taking a peek at the game files by pure curiosity, I stumbled upon localization files containing the audio dub for several languages. Turns out these are completely optional and the game boots fine without them, allowing you to shave off up to 8 gigs of your Lego Star Wars install.
To do so it’s very simple, head to your install folder by right clicking the game in your steam library and click on “Browse local files”. In there you’ll find several files named “LP_LANGUAGE.DAT“. You can remove any/all of them, so for example if you wish to play with mumble mode or your language’s dub, you still can.
And that’s all there is to it really, I’m guessing they might come back whenever the game updates so it’s up to you to delete them or not. Enjoy the free’d up storage space, and happy gaming!