Hopefully this is useful, and actually makes sense. If it is/does, feel free to stick it in one of your many reserved posts so that it's closer to the beginning of the topic.
Keep in mind, though, that nearly all of this was noted through casual observation--I didn't do any special tests or anything.
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These are the skill costs for every combination using the Human race. A "*" signifies that the listed skill cost is likely not the base skill cost for the indicated race/profession combination because the skill level was too high--see the explanation below the chart.
Code:
Skill Bar Com Fgt Thf Tnk Wrr
--------------- --- --- --- --- --- ---
Athletics 3 6 6 6 6 3
Construction 8 8 8 8 *6 8
Dodge 4 8 4 8 8 4
Find weakness 8 8 4 8 8 4
Healing 10 10 10 10 10 5
Imbue with power 10 10 10 10 5 10
Literacy 6 6 6 6 3 3
Open locks 6 6 6 3 3 6
Sailing 4 2 4 4 4 4
Survival *5 *11 7 7 7 7
Swimming 2 2 4 4 4 4
Tactics 8 8 4 8 8 8
Woodcraft 2 2 4 4 2 4
As you can see, different race/profession combinations have different skill costs.
The cost for another level in a skill will go up with every five levels in said skill, and additional costs will be incurred if the skill level is too much higher than the PC level (with the former, there is sometimes odd behavior--occasionally, hitting skill level 5 will not cause an increase in cost, but hitting skill level 6 will).
By how much a skill cost is increased by seems to be determined by the current skill cost (a cost of "2" might only increase to a cost of "3", while a cost of "6" might jump to a cost of "8"), and is possibly affected by which skill it is.