The affirmation that God is a speaker is linked to prophetic transmission and the community's doctrinal confession. Two questions must be distinguished: whether the attribute of speech is affirmed and how its nature and expression are precisely understood.
After affirming speech, one may still ask whether its reality is merely temporal letters and sounds or an eternal meaningful speech expressed through them. Affirmation of the attribute alone does not settle every philosophical elaboration.
Consequently the argument for inner speech also examines meaning and objections; it is not based only on grammatical derivation.