Since Mercedes has a supernatural talent for languages, then for me it made sense at character creation that she could know Or'zet, if for any reason just for the novelty/exotic factor. Maybe there's fluff out there that kind of contradicts my view, but from the way I see things I feel that Or'zet is a lot different than Sperethiel.
First of all, I feel that in Shadowrun, or at least in my campaigns, cultural identity still is an extremely powerful force which categorizes metahumans. Does a japanese elf feel more allegiance to japanese culture, or "elven" culture? Well it depends on the individual, but I feel it depends mostly on the environment in which the individual was raised. For example, in today's world, take a white person in the U.S.....would they feel more kinship with a white european from germany, or an asian-american who went to the same college with them? I would say by and large it would be the asian-american. Nonetheless, there would be a certain amount of ties with the german simply based on the fact that they both were of the same race. Maybe it's a bad example, but i'm just trying to illustrate the relationship between culture and meta-type in the Sixth world. Not to say that meta-type in Shadowrun is completely analogous to racial identity in today's world, but it does lend itself to some parallels. So I just feel that cultures based on meta-type are heavily complicated by ethnic identity and only meta-types which are able to form a strong infrastructure for disseminating culture are able to form a viable identity and language, like the elves do with the Tir's.
I used to also think Sperethiel was a bunch of bullshit and it's existence annoyed me until I learned about the existence of Immortal Elves, meaning a handful of elves which survived the ages since the 4th World and along with Dragons are pretty much the main source of knowledge the Sixth World has about the previous eras. At that point it started to make more sense to me that Sperethiel could within a matter of a decade become a viable language. It was these immortal elves which were the source of "elven" culture which we see in Shadowrun. Everyone else however is just a bunch of people that were born with pointy ears, nice bone structure and they don't seem to get old but aside from that they would be culturally totally human, which is one aspect I like about shadowrun. I love the aspect that all these new "races" which are genetically still considered homo sapiens are wrestling with identity. The awakening happened so recently that they would basically still consider themselves human but humanity has rejected them and they have been forced to forge a new improvised identity. It is these immortal elves and dragons who know the real truth behind the awakening and who essentially serve as guides in this turbulent quest for an identity. So if I take the following factors into consideration: formation of the Tir's which was spearheaded by a few immortal elves, the existence of magic, the exitence of linguasofts and tutorsofts........then yes, it is concievable for me that there are a good number of elves which speak Sperethiel and it's much like how modern Hebrew is today and the formation of the state of Isreal, 50% actual culture, 50% created culture.
Or'zet however was only introduced in 2057 in Dunkelzahn's will and before this point there was no real Ork Nation movement.....it was the discovery of this ancient language which made Orks realize that they, just like elves, actually had an ancient culture. The difference is there was no one around who practiced that culture and language because there are no Immortal Orks. So Or'zet as opposed to Sperethiel is much more of a symbol than an actual language which is commonly spoken. Most Orks, even in 2072, still are second-class citizens and lack any sense of over-arching identity and other than the occasional riot or Ork rights group, they don't have a viable infrastructure for instilling culture and much less language.
When I fleshed out the Crimson Crush gang, I wanted them to be an exception to this. Basically they are the only stabilizing force in these predominantly ork neighborhoods and part of the way they do it is paying tribute to recent Ork Nation ideologies. Even then though, it's more or just a tip of the hat and by and large their culture is Redmond street culture and their language is English city-speak. To reflect this I gave members of the gang a language skill of 1 in Or'zet. Sheldon, the leader of the gang is very sympathetic with the Ork rights movement and even though he himself also only knows a smattering of a few words in the language (skill of 1), he encourages the other gang members to also know a few words just for the shear sake of being able to lay a little bit of a legitimate claim to some kind of ork identity that is separate from street culture.
However, almost nobody in the actual ork neighborhoods of Seattle knows any Or'zet at all except for perhaps one or two words......they don't really spend their time thinking too much about ork identity, they're more concerned with eeking out a living. They live in the neighborhoods they live in out of circumstance and because their parents and maybe grandparents were refugees from the night of rage and years of persecution. Another factor is "human flight" to better neighborhoods.
So to sum up my long treatise on Or'zet ..... If any character is going to have Or'zet as a language skill, they better have some good background for it.......but in Mercedes case, picking up langauges for her is like going down to the mall and buying a pair of Evo thong underwear.....so i'll except it. But you shouldn't assume that orks you meet know Or'zet because practically none of them do, even Crimson Crush. If you want to culturally connect with the Crushers, very local Redmond street slang is surest bet.