I just realized that the Tiefling Wizard has an extra language... maybe that is where the other trained skill went? Perhaps you can spend one of a trained skill to acquire another language?
This would give wizards 4 trained skills!
Tieflings:
Languages: Common, choice of one other
Tielfing Wizard from D&DXP:
Languages: Common, Elven, Goblin
This would give wizards 4 trained skills!
Tieflings:
Languages: Common, choice of one other
Tielfing Wizard from D&DXP:
Languages: Common, Elven, Goblin