Each installation only includes some select language packs for console to save on installation space. Unfortunately, there are no individual language pack installations for the game. If changing your language doesn't make it available in game and it's a supported language, then you'll have to take a few steps because of that. First, you'll need to uninstall the game. Next, please create a new PSN ID and for the country, select one where the language you're after is a known main language. Make sure and select the language you're after when doing so. Next, go to the Playstation Store while logged into that account; it should take you to a localized Playstation store meant for the region that you selected with your PSN ID. Lastly, download the game from that Storefront. As long as the language is a supported language, then downloading from the store meant from that region should download the installation that includes that language in its language packs. After the game is downloaded, you should be able to switch back to your main account and play, and hopefully the language will become available in-game as you intend.