Hi sorry for late late reply my network is down for almost 2 day 
here is some progress
@atari
A newest jp voice is not in your file it is very strange don’t know why so I decide to install JTOS client to find it myself and then I found it inside patch file 152355_001001.
Here ITOS with newest jp voice (version 3 newest on j k tw tos)
here jtos version 3 voice
compare it to current one (version 2 voice base on _Yuki’s file)
it is still on testing though need more tester for other class (character with C3 is best)
Here is download link
https://goo.gl/huCdtd
I made it as an addon so after extract put it to your tos data folder like other addon
make sure a file name is correct (has a snowman in it name)
__newestjpvoicetest-v-152355_001001⛄
or just copy a snowman or other special character from other addon it should work fine.
How to change from old method (replace patch file) to new addon version file
For everyone that use Yuki’s file or other method that require you to replace a file inside tos/patch folder
pls re-verified then download either
jp voice version 2
https://goo.gl/j5KM1z
jp voice version 3
https://goo.gl/huCdtd
extract then put it inside data folder like other addons.
for everyone that never use or change ingame voice before
goto your \Steam\steamapps\common\TreeOfSavior\release
find a file name user.xml
open it with notepad
look for this line
<Sound TotalVolume="104" SoundVolume="77" MusicVolume="77" Language=""/>
change Language="" to Language=“Japanese” then save
extract 2 file above then put it inside data folder like other addons then it is done.