Hello Daniel.
Well I have them on iTunes so don't know if there are audio described dvds. They are very understandable and fun to watch.
Hth. I have never needed audio description so  you should have no problem understanding it.

Well if you are a casual watcher.
Then that's fine, but if you followed it like me, the  worse you could do was miss the end of a story arc, if you have to miss eps 1 or 2 would be the best to miss at a time but still.
One day I may buy it all but sg1 has 10 seasons, sga has 1 season ever broadcast in 2 bits and another season that never made it.
Universe which I did watch has a second season but it never made it sga has at least 4 seasons rumoured but I watched most of it back in the day.
The only scifi drama that continues is the bbc doctor who and I havn't really watched all doctors just the latest 4 or so new seasons some of which someone gave to me from a now dead server he had.
However there is so much and to own all the gate, trek who and other  stuff is just to much to pay and to much to store.
A lot of the classics died in the late 90s,  never to come again.
Out of the stuff that I have watched so far when I did, all of doctor who up to the current new season 4 was good this one I don't know I missed an ep because I had a party last week.
Out of the treck, tos, tng, voyager and ds9 were good as well as first season and only season broadcast of enterprise.
Out of stargate, the original sg1 all 10 seasons well most of those anyway.
atlantice, all of it.
and most of universe.
On an interesting note, battle star galactica which I watched the old series rocked the newer more reality based series just didn't feel right.
There are a few others like that everything from the 80s to the 90s was quite good.
but most things after 2000 are totally crap or more of the same thing.
By themselves they are not crap but if you watched the origionals like I did you really will be disappointed.
The only drama that actually differs from that is the nightrider series, the old one rocked, the new one while different, to me was quite good.

Hi.
Well this is something I forgot to mention but you can look up the transcripts of most tv shows like pitermach said. I do this often with shows like spongebob or the big bang theory when something happens that I don't understand. A lot of the time  a show's wiki will have transcripts of shows but if they don't I guarantee a transcript of a  show can be found anywhere.