It takes care of translating spell names by itself. Stick to 'english names' everywhere in your code and you'll be fine. I've tested it on the french client, works fine. There may be a few issues with pet spells though, I got to test that.
Conic area spells (11 is range, 33 is the max relative facing towards target difference (=> 66? degrees cone):
SC.CastConicSpell("Shadowflame", 11f, 33f, a => true, "ShadowFlame"),
Instant or cast AOE spells (not channeling ones):
SC.CastAreaSpell("Explosive Trap", 2, true, 1, 0.0, 40.0, a => SC.PlayerHasBuff("Trap Launcher"), "Explosive Trap"),
Channeled AOE spells:
SC.ChannelAreaSpell(string name, double radius, bool requiresTerrainClick, int minAffectedTargets, double minRange,
double MaxRange, CanRunDecoratorDelegate cond, string label)
minRange is usually 0, maxRange should be the max distance you can cast the spell at.
Have a look at the warlock rotations for pet management (forget about the StopCast composite related to pets, I just removed it). Pet spells are a bit different from your spells; they usually look like 'Felstorm(Special Ability)' instead of 'Shadowbolt'. These are the same names you could use while writing an in-game macro, so that's quite easy to find them.