That's right . First you must download and install Broken Sword 2.5 following one of the links that you will find at the original site (www.brokensword25.com). Due to the large size of the game , approximately 700 MB , it is not hosted on the server of the official site but on several other sites around the Internet (I recommend GamersHell). After you install the game , you download the english speech pack (171 MB) , unzip it and copy the new files in the game directory , overwriting the old ones (there's no automatic installer). The english voice pack also includes all previous updates for the game so you don't need to download anything else. Note that when you first start the game , the menus will still be in german. Just click on "optionen"( which naturally means "options") and select the english language.
As for the game itself , it is practically a new fan-made episode in the "Broken Sword" series , with graphics , interface and gameplay similar to the first two games , "Shadow of the Templars" ("Circle of Blood" for Northamerican gamers) and "The Smoking Mirror". It's such a professional piece of work that could have been made by Revolution and it's completely free!