The occurrence of a miracle can be used as proof for the existence of the attribute of Speech. This is because a miracle is a signal from Allah ﷻ that a claimant to prophethood is truthful, the equivalent of His saying: “this man tells the truth about Me.” And a signal is nothing by an expression of what one has signified.
From there we say: a signifier is a signifier by virtue of an attribute that subsists within them, whose existence entails this signifying. Not by virtue of the created sounds that express what is signified. And this attribute is necessarily additional to the signifier’s power, will, and knowledge. This attribute which entails the signifying is all what we mean by “speech”.
Thus, if Allah ﷻ signals information, then He is necessarily attributed with Speech. And Allah ﷻ does signal information by way of creating a miracle. So He is necessarily attributed with Speech.
 In the same way a nod signals that the one nodding has signified his approval.
 Some of the miracles He has supported our Prophet ﷺ with are mentioned here.
 And given His changelessness, this Speech is necessarily beginningless and everlasting.