Nice work

I've spent quite a bit of time recording voices for TPR (rogue, warrior, vagabond, TPR campaign briefings etc.) so I have a bit of experience doing this kind of thing, and it's quite difficult to get things to sound the way you want them. (I took lots of recordings of each action and picked the best ones)
Looking at the files in an audio editor I can see that the volume is maxing out quite regularly, creating distortion. (you can sometimes hear this as crackles like Shadaoe mentioned) To avoid this, hold the microphone much further away from your mouth. When I recorded the TPR briefings I was using a gaming headset with a fold out microphone and I found that putting the mic about level with my eyes and speaking in a normal voice gave the best results. When I did the unit voices I put the microphone about 20cm away from my face.
By doing this you will get a quieter recording which you can then amplify later. (I or someone else here can help you with amplifying it in a way that doesn't create distortion) Basically your recording should never be hitting maximum volume, because if it is, it's distorting at least a little bit. Your recording should always be less than the maximum volume.
format0.wav and storm0.wav are examples of sounds that is NOT distorted because it does not hit maximum volume

storm1.wav is an example of a sound that IS distorted because it hits maximum volume for most of the sound
Another piece of advice I learnt: Listen back to the recordings using headphones not a speaker (unless you have really good quality speakers) because it's much easier to hear the detail with headphones.
I can't judge the quality of the voice because I don't speak Dutch
If people want to test this in-game, create a folder under "data\sfx" called "speech.dut" and extract the "militia" folder into there so you end up with "data\sfx\speech.dut\militia\attack0.wav" and all the other files. Then play the game with the language set to Dutch.
Keep up the good work!
Lewin.