I used to be a court reporter.
I haven't heard of the stenomask though.
I learned how to write using a stenograph, but it takes a lot of practising to get up to the required speeds to be able to be a 'writer' so people sometimes start out as an editor and graduate onto writing after practising for months in their spare time to get up to speed. At the time I passed my accreditation test (this was quite a few years ago), there were only about 50 people in the world, outside the US qualified to do what's called realtime online editing, i.e. editing in court or arbitrations on a laptop hooked up to the stenograph, and I was one of them. Not a bad achievement for an Aspie! I had, however, been a legal PA for a few years beforehand so was fairly fluent in legalese and had good typing speeds.
I wouldn't worry too much though about the terminology. I was lucky, I had a head start, but some of fellow trainees didn't have a legal background, and they managed okay, you just spend a lot of time double checking the spelling of legal terms at first.
Where are you based? I know in the UK they still use a fair amount of latin legal terminology. There were moves to simplify language some years ago, but I think some lawyers still prefer the latin for its pomposity, gives them a learned air!
Tbh, it's one of the reasons why I get really annoyed with some of the information I've come across on the 'web about suitable careers for Aspies, and they usually recommend computer programmer, or something really brainless, like stacking shelves in a supermarket.
There's lots of structure in law, the framework of court cases and the procedures mean you know where you stand in terms of there are rules everyone has to abide by. And then the language: I know that some diagnostic criteria say that Aspies have a problem with language (strengths with logic and maths and science), but I don't know whether that's supposed to refer to spoken language and verbal communication. Either way, I've never really had that problem, I was always more of the typical 'little professor' type than the non-verbal!
I think Aspies can blend in very well in a legal environment (heck I did for years!) precisely because of the stereotype of Aspies having quite formal language. You can't get much more formal than legalese!
Legalese is like a language, and it is possible to become fluent in it. Just as some Aspies can become fluent in computer programing languages. Just get a legal dictionary, you shouldn't have a problem, honestly!
They test your grammar because... here's the shocker... y'know how everyone assumes that a court transcript is 'verbatim', as in what appears on the transcript is *exactly* what is said in court? Ain't so. And that's where the grammar comes in.
Again, don't know whether you're based in UK or US or elsewhere, but I know that in England and Wales at least, plus HK and Singapore, it is only witness evidence in a criminal trial that will be 100 per cent absolutely definitely verbatim. In civil cases, the editor of the transcript is given a little bit of leeway to 'tidy up' the transcript. Nothing major of course, nothing that would change the meaning.
For example, if counsel says: "I refer you to... erm... page 63 in... erm... bundle A [of the court documents], where you will see that... oh sorry, I meant page 92 in bundle B... do you recall sending that letter..."
You'd tidy that up to: "I refer you to page 92 in bundle B; do you recall sending that letter?"
Natural speech involves lots of umming and aahing, which as a court reporter you'd edit out. You'd also tidy up what they call false starts... where someone starts a sentence but changes their mind after they've started and corrected themself. And you'd correct mistakes like referring to the wrong page and bundle number.
It just makes the transcript much easier to read when the lawyers are going through it to prepare their cross-examinations and stuff.