All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
The scholars reconciled between these verses by saying that the non-Muslims will be allowed to speak at certain times and prevented from speaking at some other times; for instance, the prominent scholar Al-Ameen Ash-Shinqeeti said in Daf’ Eehaam Al-Idhtiraab ‘an Aayaat Al-Kitaab (page 249):
“The saying of Allaah (which means): {This is a Day they will not speak. Nor will it be permitted for them to make an excuse.} [Quran 77:35-36] This verse means that the people of Hellfire will not speak and they will not seek excuses.
But there are some other verses which prove that they will speak and seek excuses; such as the sayings of Allaah (which mean):
• {"By Allaah, our Lord, we were not those who joined others in worship with Allaah."} [Quran 6:23]
• {…and [who] then offer submission, [saying]: We were not doing any evil.} [Quran 16:28]
• {…rather, we did not used to invoke previously anything.} [Quran 40:74]
• {By Allaah, we were indeed in manifest error. When we equated you with the Lord of the worlds. And no one misguided us except the criminals.} [Quran 26:97-99]
• {Our Lord, these had misled us...} [Quran 7:38]
As well as other verses.
The answer to this is as follows:
1- There are phases on the Day of Resurrection; at some phases, they will speak, and at some other phases, they will not speak.
2- They will not speak of something that will benefit them, and speaking of what does not benefit them is like not speaking at all.
3- After Allaah says to them (what means): {Remain despised therein and do not speak to Me.} [Quran 23:108]; they will not speak anymore and what remains for them is only violent exhaling and inhaling.
Allaah says (what means): {And the decree will befall them for the wrong they did, and they will not [be able to] speak.} [Quran 27:85]
This third instance relates to the first one.” [End of quote]
Allaah knows best.