When I run the instaler in German locale installer UI is showing in German but the application UI is not showing in German using NSIS - nsis

Question

When I run the installer in the German locale, installer UI is showing in German but the application UI is not showing in German. Instead it is showing in English.
For the Installer UI to work as per the locale I have created separate .nsh files (!include "CustomEnglish.nsh",!include "CustomGerman.nsh",!include "CustomItalian.nsh") and included those in my .nsi file. So it is working as expected.
For the application UI to work as per the locale, I am using the below check based on the Language and placing the files (created separate resouce dlls for each language) in the Installed directory.
Is it the correct way to place the dlls or files based on the locale in the Installed directory?
And also I am not using the statement !insertmacro MUI_LANGUAGE "English" in this .nsi file. Because this statement I am giving in the !include "CustomEnglish.nsh" (I have also attached CustomEnglish.nsh for the reference)
Please help me why the application UI is not showing in German?
Below is the complete code:
!include "MUI2.nsh"
!include x64.nsh
!include WinVer.nsh
Name "Millinnium 4.0"
RequestExecutionLevel admin
;RequestExecutionLevel user
; Below is the include file to check the conditions (If and else)
!include LogicLib.nsh
;Customizing the Welcome Text
!insertmacro MUI_PAGE_WELCOME
!insertmacro MUI_PAGE_DIRECTORY
!insertmacro MUI_PAGE_INSTFILES
!insertmacro MUI_PAGE_FINISH
!insertmacro MUI_UNPAGE_INSTFILES
${EndIf}
SectionEnd
;--------------------------------
Section "Uninstall"
SectionEnd
CustomEnglish.nsh
!insertmacro MUI_LANGUAGE "English"
!define ApplicationName "Millinnium"
LangString welcometitle ${LANG_ENGLISH} "Welcome to the ${ApplicationName} Setup Wizard"
LangString welcometext ${LANG_ENGLISH} "The Setup Wizard will install ${ApplicationName} on$\r$\nyour computer. Click Next to continue or Cancel to exit the$\r$\nSetup Wizard."
LangString licensetitle ${LANG_ENGLISH} "End-User License Agreement"
LangString licensesubtitle ${LANG_ENGLISH} "Please read the following license agreement carefully"
LangString licensecheckboxtext ${LANG_ENGLISH} "I &agree to terms in the License Agreement"
LangString mydirtoptext ${LANG_ENGLISH} "Install ${ApplicationName} to:"
LangString mydirtitle ${LANG_ENGLISH} "Destination Folder"
LangString mydirsubtitle ${LANG_ENGLISH} "Click Next to install to the default folder or click Browse to choose another"

Answer 1

I found the root cause of not displaying the UI in other language (for eg, French). It is because i didn't include the language specific folder (for eg, "fr" that has resources.dll) in "INSTDIR".
To include that I have written the below lines of code and it is working now:
SetOutPath $INSTDIR\fr
File /a /r "C:\Code\EMR\bin\x86\Release\fr\"