here is a fairly quick work-around
in windows explorer find the Apple Software Update folder in program files or programFiles (x86)
goto the "SoftwareUpdate.Resources" folder
1. sub folder "en.lproj" then right click the "SoftwareUpdateLocalized.dll" file and copy
2. goto the folder of the language the ASU is using example "zh_CN.lproj" for chinese and right click the "SoftwareUpdateLocalized.dll" to "SoftwareUpdateLocalized.bak"
3.then paste <ctrl+v> "SoftwareUpdateLocalized.dll" from the "en.lproj" folder into the "zh_CH.lproj" folder
Next repeat the same process for the "SoftwareUpdateFiles.Resources"
goto the "SoftwareUpdateFiles.Resources" folder
1. sub folder "en.lproj" then right click the "SoftwareUpdateFilesLocalized.dll" file and copy
2. goto the folder of the language the ASU is using example "zh_CN.lproj" for chinese and right click the "SoftwareUpdateFilesLocalized.dll" to "SoftwareUpdateFilesLocalized.bak"
3.then paste <ctrl+v> "SoftwareUpdateFilesLocalized.dll" from the "en.lproj" folder into the "zh_CH.lproj" folder
run ASU and you should now see everything in english at least until ASU updates itself.
Former apple advisor