They are different things.
First of all, Microsoft distinguishes between
- editing language (whatever content you're typing)
- interface language or display language (the user interface elements on the screen; things like "File", "Start", "View" etc)
- help language (the text in the Help screen)
- tooltip language (in the little popup rectangles when you hover over a control)
Now I have no idea why they split it up into so many items, and give the user the ability to set each of those independently; you have to ask them. But yes, you can write German documents on Word with an Italian user interface, French tooltips and Swedish help screens if you wish.
Anyway, for the editing language, you have the proofing tools, which include spell check, grammar check etc. These tools aren't available separately, but some versions of MS-Office include more than one language. See Localized versions of Office.
For different interface languages, you can download LIPs (Language Interface Packs) for free. However, those LIPs are only available for a handful of languages, none of them very widespread. For instance, English, Chinese or Spanish are not among them, to name a few. Here is the list.
Then there's the help language texts, which are also not available separately AFAIK.
And finally, the tooltip texts, which are. You can download those for free here.
Then the language packs; those are complete packages of language features (containing editing, display, help and tooltip texts) which are not available for download, but which can be purchased online.
Or rather, they used to be; all the links for those language packs redirect to the Office 2013 purchase page these days. Which is a shame, since this looked like it was what you wanted. Sorry.
And I'm not sure which files you downloaded. The files downloaded from Microsoft have much more descriptive names, such as ScreenTipLanguage_en-US_32Bit.exe or languageinterfacepack-x64-af-za.exe.
That's what I know. I do realise your question is almost a year old, but I hope it helps future visitors!
A collegue of mine told me about the Digital River storage site, where you can download those language packs, with the same filenames as you mentioned even. I wasn't aware of that; Microsoft's site never mentions this, as they are no longer interested in supporting Office 2010, apparently. Oh well.