[subject] + [verb] + [person] + [thing]
[subject] + [verb] + 了 + [person] + [thing]
A small set of verbs takes two objects: the person who receives, then the thing. Nothing goes between them, and the person always comes first.
The verbs are ones of handing something over, in either direction: 给, 送, 还 "give back", 借 "lend", 找 "give change", 教, 告诉, 问. 叫 also works for "call someone something".
了 goes straight after the verb, before the person.
English can put the thing first: "teach Chinese to us". Chinese can't.
Most verbs don't take a person straight after them. 写, 做, 买 and 打电话 need 给 + person in front of the verb.
说 doesn't take a person either; use 告诉, or 跟 + person + 说.