Hi, guys, and welcome to the forum ... although like everybody, I'm really sorry you had to seek us out.
My symptoms started with speech slurring, too. This is called "bulbar onset," because it affects a certain part of the brain called the "bulb." Although most PALS (patients with ALS) start with weakness in the limbs, it is not uncommon for it to start with speech and swallowing.
It took about 9 months in my case for swallowing problems to develop after my speech started to slur. Now, at 2 1/2+ years, it is spreading into my hands and arms, although I'm still functioning (driving, keeping house, etc.)
Every case is different ... you will hear that over and over, and it's true. There are two things you can do to slow down the progression. One is a medication (very expensive) called Rilutek, which statistics show extends life by several months. The other is diet: Losing weight speeds up progression, and studies have shown that maintaining weight or even gaining, will extend the patient's life even more than Rilutek. So do everything you can to help get calories into your PALS.
As far as what happens next: The doctors will keep a very close eye on your PALS' breathing and swallowing, which can be affected.
Also, ALS affects the part of the brain that controls emotional reactions, so your PALS may burst into laughter or tears at strange times. Other emotional reactions from ALS are anger and frustration. There are ways to help with breathing and swallowing, and meds to help control the emotional outbursts.
I recommend that you get in touch with the ALS Association. They are a wonderful organization, and they'll assign you reps or case managers who can help guide you.
Take care of yourselves, too !