Three Days Or Three Nights?

The author, supposedly Allah, has Zakariyya given a 'sign' not to speak.

S 3:41 He said: Lord, make me a sign. He said: Your sign is not to speak to people for three days except with gesture. And mention your lord much and glorify in the evening and the early morning.

S 19:10 He said: Lord, make me a sign. He said: Your sign is not to speak to people for three nights straight.

Is he mute or does he simply not speak? Why do the accounts differ? Did 'Allah' say three days or three nights? Did Allah turn up and speak to him?

Did Allah Come?

An Examination of the Parallel Passages of the Quranic Text: CONCILIATION OR CONFLICT