hey masanori,
is your folder really named ja_JP and the file ja_JP.com_easysocial.ini ?
if so then this won't work at all because it has to be a "-" instead of "_" , so the folder would be ja-JP and the file ja-JP.com_easysocial.ini

if the folder and filename is correct in easysocial there are even other things to check: because the com_easysocial file is not the only one used to manage the translations. in total there are about 70 files (frontend and backend) that are used for language handling so even if the mentioned file loads correctly but you don't have the other files you'd still see lots of things in english...

hope that helps

oops sorry Alex,

Yes folder and filename are correct. sorry.

I understand what you say but when I disable en-GB.com_easysocial.ini (in language/en-GB) the site goes like attached picture.
This means it's referring that ini file right?

Hello,

Is it possible for you to provide us with the back end and FTP access to your site to check on this issue?

Hi Mark,

Thank you for your help.
Please find FTP info....

Hi,

The language file is actually loaded but because the language is not fully translated hence the English language is used as the fall back.

If you go to the file: /language/ja-JP/ja-JP.com_easysocial.ini, you will see that most of the lines have a ; at the start, in which that indicates that the line is ignored. You try by translating a few lines and remove the ; in front of each line, and you will see that the language string is reflected on your site.

Jason,

Oh, Thank you.
You're 100 % correct.
I'll remove " ; " .

Thanks for updating and glad that your issues are resolved now.