a man is in love with a woman, but has his friend pretend to be him and talk to the woman?
The whole movie his friend does all the communication with her, towards the end of the movie, the friend has also fallen in love with her too.
Did the articulate man who stays in the shadows have a very long nose? If not, then this is definitely the wrong answer, and I hope someone else will help. But your description makes me wonder if the movie could be the 1987 romantic comedy Roxanne, which was loosely based on the play Cyrano de Bergerac. Or maybe even a different film version of that play. There have been many film versions of the play, including fine versions with Jose Ferrer and Gerard Depardieu in the title role. In Roxanne, Steve Martin plays a smart and sensitive fireman who loves Roxanne (played by Daryl Hannah). But Martin has a freakishly large nose, and he lacks the self-confidence to tell Roxanne how he feels about her. When a good looking but extremely dim friend of Martin wants to date Roxanne, he provides the kid with the romantic words to win Hannah over. But it tears him apart to see her falling in love with his friend, and only because he is pouring out his heart through his dim-witted friend.