We faced an issue in English language pack installation/detection when SharePoint is installed in different language than English (en-us). So we have Finnish version of SharePoint 2010 and have added the English language pack but that will be skipped because the AutoSPInstaller detects the installed languages reading InstalledLanguages from registry. The problem is that when SharePoint binaries are installed also the EN-US is added to InstalledLanguages in registry even that SharePoint is installed in different language like Finnish.
.#Get installed languages from registry (HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office Server\$env:spVer.0\InstalledLanguages)
$installedOfficeServerLanguages = (Get-Item "HKLM:\Software\Microsoft\Office Server\$env:spVer.0\InstalledLanguages").GetValueNames() | ? {$_ -ne ""}
Now we just commented all the lines which are related to checking installed languages in AutoSPInstallerFunctions.ps1 to be able to complete the installation correctly.
.#Get installed languages from registry (HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office Server\$env:spVer.0\InstalledLanguages)
$installedOfficeServerLanguages = (Get-Item "HKLM:\Software\Microsoft\Office Server\$env:spVer.0\InstalledLanguages").GetValueNames() | ? {$_ -ne ""}
Now we just commented all the lines which are related to checking installed languages in AutoSPInstallerFunctions.ps1 to be able to complete the installation correctly.