As customers are reporting issues with installing language packs, Microsoft is scrambling for explanations as to why the packs aren't fully working.
Today, Raymond Chen a Microsoft Forums community manager is issuing a new explanation that is equipped with localization diagrams as to why languages such as Portuguese and Turkish are having trouble, in certain situations, installing.
Fortunately, for those of use not adapt at reading diagrams about localization, Chen summarizes the entire incident.
What's going on is that Portuguese (Portugal) and Turkish are in the second case: A partially-localized language pack. In particular, console applications and PowerShell Console UI are not localized and fall back to English.
This also explains why German doesn't have the same problem: German is a fully-localized language, including console applications and PowerShell Console UI.
While having an explanation may assuage some users fears, it seems thus far, Microsoft doesn't have a fix to issue. We'll update accordingly with new information as it's made available.