the second number in nations is for desert warriors... I noticed that most of arabian soldiers has other names than arabian so I tried it...
next what I found is that you can't add new nation to bio.txt, but you can add your own names
At the end of the file there is this code:
Freq_band 1 20
Freq_band 2 60
Freq_band 3 15
Freq_band 4 5
I think this is probability in % for names with marked numbers for example if there is name
then this name is marked as russian name with mark 2 which means its probabity to generate from russian names is 60%, so the russian names marked with RU2 are generated the most, russian names with RU4 are generated only sometimes... but I think this is not really important.
It is just for info