Comment 3 for bug 521163

have you installed the package named "language-selector"?
you might need to add CJK specific fontconfig files
by installing this package, and then activate Japanese
settings by

 sudo fontconfig-voodoo -f -s ja_JP

this is a Ubuntu hack for solving the CJK language
conflict. I've proposed a more systematic solution
to fontconfig upstream, but I've got no response yet,
see

http://bugs.freedesktop.org/show_bug.cgi?id=20911

Peter Maydell wrote:
> Results of running firefox with FC_DEBUG=1. Interesting part (I think):
>
> Sort Pattern has 16 elts (size 32)
> family: "Bitstream Vera Sans"(w) "DejaVu Sans"(w) "WenQuanYi Zen Hei"(w) "DejaVu Sans"(w) "Nimbus Sans L"(w) "AR PL UMing HK"(w) "AR PL UMing CN"(w) "Waree"(w) "Loma"(w) "Garuda"(w) "Umpush"(w) "Norasi"(w) "Mukti Narrow"(w) "VL Gothic"(w) "Sazanami Gothic"(w) "UnDotum"(w) "Lohit Gujarati"(w) "Lohit Hindi"(w) "Lohit Punjabi"(w) "Lohit Tamil"(w) "FreeSans"(w) "Umpush"(w)
> slant: 0(i)(s)
> weight: 80(i)(s)
> width: 100(i)(s)
> pixelsize: 13.3333(f)(s)
> antialias: FcTrue(s)
> hintstyle: 1(i)(s)
> hinting: FcTrue(s)
> verticallayout: FcFalse(s)
> autohint: FcFalse(s)
> globaladvance: FcTrue(s)
> rgba: 1(i)(s)
> lang: "ja"(s)
> fontversion: 2147483647(i)(s)
> embeddedbitmap: FcTrue(s)
> decorative: FcFalse(s)
>
> First font Pattern has 20 elts (size 20)
> family: "文泉驛正黑"(w) "WenQuanYi Zen Hei"(w) "文泉驿正黑"(w)
> familylang: "zh-tw"(w) "en"(w) "zh-cn"(w)
> style: "中等"(w) "Medium"(w)
> stylelang: "zh-tw"(w) "en"(w)
> fullname: "文泉驛正黑"(w) "WenQuanYi Zen Hei"(w) "文泉驿正黑"(w)
> fullnamelang: "zh-tw"(w) "en"(w) "zh-cn"(w)
> [etc]
>
>
> ** Attachment added: "FC_DEBUG=1 log from firefox"
> http://launchpadlibrarian.net/39108866/fc.log
>
>