Lost Chapters are Space Marine Chapters that have been destroyed. Some were annihilated in one sudden strike, while others were slowly diminished through attrition, being unable for whatever reason to recruit new marines fast enough to replace combat losses. Information about such chapters is often lost during the millennia and all-too scarce.
The style of speaking I was told is less rigid in sentence structure to that of regular Space Marines given their isolation, but they still possessed the same dedication and loyalty to the Emperor despite their grim circumstances.
This voice was recorded and edited for me some time ago by some folks from DoW modding community in accordance with how they wanted it to sound =).
Music Used: Space Marine Theme 2 from Dawn of War II
Link: www.youtube.com/watch?v=AIJ8GSg55UQ