If you have Office 2007, you can use the same language packs for Office 2007 and Office 2010. After Office 2010, there is no longer a separate Office 2010 product language pack. You can download the default language pack for Office 2010 from the same page by clicking the Office 2010 download link. For Office 2007 you can download the language pack for Office 2007 from this page: http://www.microsoft.com/office/downloads/default.aspx
This page does not provide a link to the language packs, but it does provide some useful information. From this page you can choose to download the default language pack, a different language pack or the language pack for your region. If you are unsure which download to choose, just go for the default language pack.
The only office applications that are affected by this is the Office Product Language (Default) Language Packs. The Office Product Language (Default) Language Packs, however, only affect the installation process and a dialogue box appears on the Microsoft Office installation CD/DVD. This is where you have to choose the language that you want to use when you install Office.
Language packs come in two variants, the Office Product Language (Default) and the Office Product Language (Alternate). Default language packs are the default locale for your computer and you will have the same language experience in all Office applications. Alternate language packs are languages that are not officially supported by Microsoft. They may be less comprehensible and may only be available for a few documents. These languages are for your own interest and the possibility to choose different languages in Office applications. For the sake of consistency, I will refer to both sets of language packs as language packs in the rest of this article.