If I'm not mistaken, those aren't actually translated. Rather only the names of things need to be translated.
Would change to:
#showtooltip Mortal Strike
/cast Mortal Strike
That should function as expected and cast the Mortal Strike ability.
#showtooltip Golpe mortal
/cast Golpe mortal
Use would have the same issue unless it were using a specific InventorySlotID like /use 13 or /use 14 to use a trinket. If it is referencing an item by name, the name needs to be updated.
Equipslot will need to change the name of the item you are equipping, the InventorySlotID does not change and neither does the command.
Conditionals will have the same base value.
The pet would not change, however the value associated with the conditional "felhunter" would.
Finally, unit ids are the same as well so values like target, mouseover, targettarget, focus, player, raidN, partyN and so on are not translated.
/cast [@player] Innervate
Bold doesn't translate, underline does.
Hope that helps.
"In anything, if you want to go from just a beginner to a pro, you need a montage." /w TankSpot WTB Montage for Raiders.