Dative subject constructions with 「もらえませんか」

Question

Back to basics. I have heard sentences similar to these ones online that attest the same structure

私も弾いてみたい、と思った私はすぐさま「私にも教えてもらえませんか。」と願い出ました。(source)

あとで時間があったら、その秘訣を私にも教えてもらえませんか。(source)

アーモンドさん（左）「私に貸してもらえませんか？」(source)

是非とも夢ある皆さんの力を私に貸してもらえませんか？(source)

Why に? In all of these sentences isn't the subject 「私」? The agent of the action is the other party, and 「もらう」determines the subject is the benefector of the action. What am I missing here? There seems to be a function fusion of indirect object with subject of sentence.

Answer 1

As noted in the comments by Leebo, Eddie Kal, and A. Ellett, the に marks the agent of actions in certain constructions. We sometimes use by in English in a similar fashion.

In the ～てもらう construction, consider that the agent of the verb もらう is getting (もらう) something done (the ～て verb) for them. This is, in some ways, not far from the passive, where に is also used to mark the agent (the doer of the action) and は or が to mark the patient (the receiver of the action).

• Passive:
  • 私[は]{●}先生[に]{●}教え[ら]{●}[れ]{●}[た]{●}
• "Getting":
  • 私[は]{●}先生[に]{●}教え[て]{●}[も]{●}[ら]{●}[っ]{●}[た]{●}

We might express this in English as:

• Passive:
  • I was taught by the teacher
• "Getting":
  • I got taught by the teacher

Note: In English, the two are so close that they are essentially fusing in modern colloquial usage. The "getting" sense of "receiving" is thus often expressed in a slightly wordier fashion, to avoid ambiguity:

• "Getting" with explicit "receiving":
  • I got the teacher to teach me

The key point to remember for ～てもらう constructions is that they are similar to the passive, and the agent (doer) of the ～て verb generally takes に.