polyglot
Lojban is full of all kinds of different dialects nowadays - all the new kids with their pos and taus and kis and vois... The worst thing is you have no way of systematically figuring out what dialect a sentence is in, unless it happens to parse in only exactly one of them!
Well, there's always a compromise. Just write sentences that parse in all dialects! ...Wait, you didn't say they're not allowed to contain the forbidden words..? Just that they need to parse in both cases..?
Polyglots (or sorbauterge'a in lojban) are a Lojbanic form of word play (poetry?) that consists of writing sentences that parse in more than one cmavo-swapping dialect, despite containing some cmavo that have been swapped - of course, not just in some trivial way like quoted with zo. Bonus points if both meanings are semi-plausible lojban sentences. Even more bonus points if the meanings are quite close (it's probably impossible to end up with the exact same meaning).
Simple polyglots
Some easy examples for the most common cekitau swaps.
ki
.i le banli noi pu ki barda spoja ba se xenru
Unswapped: The great thing, which blew up in a huge explosion, it was going to be regretted.
Swapped: The grand event, before which there was a huge explosion, will be regretted.
ce
.i mi co'arkai lo ka klama le tcadu ce le ricfoi
Unswapped: I'm starting to go to the city-and-forest area.
Swapped: Someone's starting to go away from me, towards the city, through the forest.
tau
.i le skepre cu xusra lo du'u ma'a na djuno tau sy
Unswapped: The scientist said that we don't know S (as in, capital S, which is distinct from small s - perhaps S is the name of a conjecture)
Swapped: The scientist said that we don't know about them (the scientist).
voi
.i la melbi voi banli cu noltru le vi gugde
Unswapped: Melbi the Great is the monarch of this country.
Swapped: Someone Great In A Beautiful Way is the monarch of this country.
Double polyglots
A multiple polyglot is one that contains more than one distinct cmavo being swapped: here some examples of double polyglots.
jboponei
Sentences for jboponei can be constructed in a similar style to the simple polyglots above, but jboponei presents a unique challenge: making a sentence involving both po and nei:
.i zo'e po mi gleki nei xusra
Unswapped: The thing of mine asserts this sentence happily.
Swapped: Someone asserts that I'm happy.
tei and foi
Finally a polyglot for two obscure cmavo for creating compound letterals, swapped into nai (paralleling to'e, already proposed before) and fi'o respectively.
.i catlu .au tei .a'y .e'y foi pa moi fa .o'y
Unswapped: I want O to be the ash-first to watch (maybe "ash-one" is a number)
Swapped: Firstly, I don't want O to look at AE.
Name origin
In programming, a polyglot is a program valid in multiple programming languages, resulting in the same or different outputs when run in each of them. An analogical idea can be applied to sentences in human languages, though it's probably difficult to come up with interesting examples since natural languages are much more different from each other than programming languages are.