Rashi on Exodus
הם המדברים וגו׳ THESE ARE THEY WHO SPAKE TO PHARAOH — It was they who received the command to speak to Pharaoh (cf. v. 26), and it was they who carried it out by actually speaking to him (cf. e.g. Exodus 7:7).
Rashbam on Exodus
הם המדברים, in connection with דבור, speaking, Moses is still mentioned first followed by Aaron, although in order of birth Aaron preceded Moses, being the firstborn.
Sforno on Exodus
הם המדברים, they were fit to be the spokesmen to Pharaoh and to be listened to by him with respect.