I want to change the Middlename/Initial text to the german translation in my register form. But where do I need to fix it? The only place where I found this text was in two core foulders.
translation process,you can do easily
Check how translation works:
For your case you can do this:
app/design/frontend/<package>/<theme>/locale/Your Language Code/translate.csv
"Middlename/Initial text","Your Text In German"
add this file