Faith come from hearing, meaning hearing the Lord speak to us.
Hmmm, let's assume you're correct here, and that hearing = hearing the Lord speak to us.
Ok. Let's pull out the full verse for some resemblence of context... "So then faith cometh by hearing, and hearing by the word of God." Romans 10:17
Now we substitute the word 'hearing' with your definition of 'hearing the Lord speak to us', and we end up with...
"So then faith cometh by [hearing the Lord speak to us], and [hearing the Lord speak to us] by the word of God."
So, we hear the Lord speak to us by the word of God. Probably not where you intended to go, considering you only used part of the verse, and came to a different conclusion.
BTW, the 'word of God' is defined in the preceeding verses as the gospel message being proclaimed through preachers, not by the guidance of some inner voice.
But what may some ask is the gospel being preached? Glad you asked.
1 Cor 15:1-8
"Now, brothers and sisters,
I want to remind you of the gospel I preached to you, which you received and on which you have taken your stand. By this gospel you are saved, if you hold firmly to the word I preached to you. Otherwise, you have believed in vain.
For what I received I passed on to you as of first importance: that Christ died for our sins according to the Scriptures, that he was buried, that he was raised on the third day according to the Scriptures, and that he appeared to Cephas, and then to the Twelve. After that, he appeared to more than five hundred of the brothers and sisters at the same time, most of whom are still living, though some have fallen asleep. Then he appeared to James, then to all the apostles, and last of all he appeared to me also, as to one abnormally born."
So the gospel preached was one founded in the scriptures, and it was by the hearing of this gospel that faith comes, and this gospel is what Paul refers to as the 'word of God' in the Romans passage.