When speaking colloquially and reporting speech, you can use any of the four grammar particles to show who the quoted speech was directed towards - 한테, 에게, 보고 and 더러:
한테:
친구가 저한테 바닥이 너무 미끄럽다고 했어요.
My friend told me the floor was very slippery.
에게:
친구가 저에게 바닥이 너무 미끄럽다고 했어요.
My friend told me the floor was very slippery.
보고:
친구가 저보고 바닥이 너무 미끄럽다고 했어요.
My friend told me the floor was very slippery.
더러:
친구가 저더러 바닥이 너무 미끄럽다고 했어요.
My friend told me the floor was very slippery.
In the case of 더러, 나 + 더러 and 너 + 더러 become 날더러 and 널더러 respectively:
친구가 날더러 바닥이 너무 미끄럽다고 했어.
My friend told me the floor was very slippery.
누가 날더러 그걸 할 수 없대?
Who says I can’t do that?