The audio that you're referring to is a drill instruction in English.
"Ready, Port Arms, Quick March."
You can hear the original audio sample here (followed by the sound of marching).
Interestingly, the writer/composer for the Hell March, Frank Klepacki
simply took it off of a sample clip library of military sounds and was blissfully unaware of what it actually said. It just sounded good to him so he included it.
Frank: I wrote the whole song that day and as I was sifting through those, you know, sounds of military marching and whatnot I started hearing these like muffled commands being yelled out, you know, and I was just like 'okay, well maybe I'll throw that in too', you know, it's just because it seems like it fits the tempo of the song so I picked one that I thought sounded cool and I had no idea what he was saying and and even the people in the office we're trying to figure it out, like then they're like 'what is he saying?', like some of my favorite the things people thought he said was "eat my pants / feed my plants" it's not necessarily English or even Russian
I mean it was very obscure because it's not really defined, you know, it's not clear at all. I thought, you know, I was trying to figure out "well if it's in English what is he saying?" you know and I, at first, I thought it sounded like like "we want war or wake up" is what I thought it sounded like. I didn't say that's what I thought it was, yeah, so I said that in an interview a couple of times and it went around as being like this 'this is what Frank said he says "we want war, wake up" and then everybody started countering going 'no, that's not what it says it's Russian and it's German, it's this, it's that' and the most popular other thing that came back was that it's a German phrase that says 'die waffen lech an' which is 'ready your weapons' in translation and I'm like 'well that makes sense, you know', so so I kind of went with that as 'okay, yeah, that works, I'll go with that definition, that's fine you know'. I wasn't there to record that guy, so I don't know for sure exactly if that's what he thing but it sounded pretty cool so I said 'yeah, sure, why not? Let's make it that.
Interviewer: Unless you still have the receipt for that SFX library that's good enough for me!
Frank: Yeah, but like I said, unless somebody can track down that guy who said that command personally and asked him to clear it up, you know, then then you'll have your answer, but until then I'm going with the German version.