1) Go to your steam Library
2) Locate the .hack game in your collection of games
3) Right click on game select properties from the drop down
4) Navigate to Local Files on the left
https://steamuserimages-a.akamaihd.net/ugc/1908982397672090957/74302C66978222AC679AAE324595AB814AE3CB4D/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false
It now displays your .hack installation location to the left of "files:"

5) Navigate to that location on your computer and you will see the steam folder where all the games you have downloaded to that hard drive are located
6) Open the following folders in this order:
steam library
steam apps
common
hackGU
cmn
data
data
sound
PC
(In photos you will see my installation location on my F: drive meaning the location the sounds folder is for me is "F:\SteamLibrary\steamapps\common\hackGU\cmn\data\data\sound\PC")
https://steamuserimages-a.akamaihd.net/ugc/1908982397672091533/731C31DEE3C853392B2D4A0BCB9B075F12EA7B41/?imw=256&&ima=fit&impolicy=Letterbox&imcolor=%23000000&letterbox=false
7) At this location you will see two folders JP/US you will need to change the US folder name to JP (folders cannot be the same name so you can change JP to JP_ first then change US to JP)

Once you start up the game it will now be in the dubbed version if you want to change it back just rename the now JP folder to US the rename the JP_ to JP

Hope this helps :)