Speech of Allah: Frm the Attributes of Allah is that He speaks with a speech that is pre-existent. He causes whomsoever He wills to hear it. Musa heard it frm Him without there being any intermediary.
Jibreel heard it, as well as whomever He permits from His angels and messengers. He, the One free from all defects, will speak to the believers in the Hereafter and they will speak to Him.
He will grant them permission & they will visit Him. "& to Musa, Allah spoke directly." 4:164 "He (Allah) said: 'O Musa, I have chosen you above men by My messages, & by My speaking (to you)." 7:144
The Quran Is The Speech Of Allah:- It is the plain Book of Allah and His firm rope. It is His straight path and the revelation of the Lord of the universe.