What samples or knowledge do we have of the black speech created by Tolkien? Having read a decent amount of the legendarium (Silmarillion, LotR, Hobbit, Children of Hurin, and some of the Lost Tales) the only occurrence I am aware of is the inscription on the one ring.
Am reading through LotR now, and have just finished H, Lost Tales, R, FG, etc. so the memories are still pretty fresh.
The Ring verse is the longest bit of Black Speech, followed by Grishnákh's bit of invective towards Ugluk. Other than that, there's only a couple individual words (like snaga, slave and ghash, fire) to be found.
Tolkien himself wrote as much in a letter (No. 144) to a reader of page-proofs (presumably of LotR): ...[Black Speech] only occurs in the Ring inscription, and a sentence uttered by the Orcs of Barad-Dur and in the word Nazgúl.
A related query on the Black Speech.