1. 1 on gloss
2. 1 on class

On gloss:

zo si si zei fa'o in sense "lojban cmavo"

x₁ is a nonsense zei-lujvo using parts x₂, silly by standard x₃.

On grammatical class:

si

erase the last Lojban word, treating non-Lojban text as a single word.