The refreshed Japanese Installers that were released on December 10th 2014 had an issue in detecting the platform's Japanese language at installation time and so was defaulting to English.
While we are going to refresh the Japanese installers, if you need to go ahead with the current installers itself, you can use one of the following workarounds.
1) You can force the installer to run on top of JRE version 7 instead of the default JRE 8 that is in-built into the installer.
To do this, you should have JRE 1.7 on your machine.
Open command prompt (Open as Administrator in case of Windows) and run the following command.
>C:\downloads\ColdFusion_11_WWEJ_win64.exe LAX_VM "C:\Program Files\Java\jre7\bin\java.exe"
Please change the paths as per your installer location and JRE/JDK location. And also please use 64-bit jre for 64-bit version of ColdFusion installer and 32-bit JRE for 32-bit ColdFusion Installer.
2) Instead of #1, you can use the following method also if you are comfortable running the installation in English itself and after installation you can change the language that ColdFusion runs on to Japanese.
Open the file C:\ColdFusion11\cfusion\bin\jvm.config and search for -Duser.language=en and replace this with -Duser.language=ja and restart the server. ColdFusion server will now in Japanese itself.