Thought I'd add my two cents too. Don't go nuts yelling or talking to her when she's barking, or she might think you're barking with her. I've seen an old lady with a high yappy voice try to get her yorkie to stop barking and honestly I could see the dog thought she was yapping at me too rather than at him to stop. One simple firm command and then use silent body language like blocking or taking hold of her collar to stop her and get her attention to do smething else like then commanding her to sit or lay down.

For the record, Autumn knows how to speak on command too, but it doesn't stop her from barking at something. Good thing she rarely barks.