Scripts

function AlaricSpec()
    while 1 do
      if KnowHeroSpell("Alaric", SPELL_HASTE) then
        TeachHeroSpell("Alaric", SPELL_SLOW)
      end
    sleep(1)
    end
end
  
startThread(AlaricSpec)

The "Trigger not found" error in the console is not related to this code. You probably have an error in the trigger somewhere earlier, which interrupts the further execution of the script - including Alaric's specialization. Look for where you made a mistake in the trigger name!