Hi, Marcia ... My speech problems started in March, 06, so I am going on three years. In the first year, speech therapy actually helped my speech a lot ... I was almost back to normal, when I had to have a small surgery, and when I woke up from that, my speech was really affected, and has gotten progressively worse.
Your sister sounds a lot like me ... same symptom progression (and same stubborness!). I know how she feels; I've had a neuro actually make jokes about ALS to me (he diagnosed me with MG and told me if I had ALS I'd "be six feet under by now." Ha, ha, really funny.) It's only been in the last six months that it has progressed beyond the bulbar symptoms, so that's two years of bulbar only.
I'd urge your sister to see a neuro again ... I don't blame her for not wanting to, and with a progressive disease like this, it may feel as if there's no point. But, there ARE things they can do to slow it down, and also to make her a lot more comfortable. I'm sure she wouldn't mind a little more energy, and advice on swallowing, and things to help her breathe better. Above all, tell her she's got to keep her weight up ... she should do whatever it takes to keep from losing weight. This will slow it down.
Is there a university clinic near you? I'm from Youngstown originally and should know, but am not sure where Hamilton is. Ohio has some top-notch university clinics.
Tell her one stubborn old lady on the ALS forum is begging her to see another neuro, and get a full evaluation and some help managing all this.
Hang in there ...