Relative clauses
Relative clauses function as modifiers and specify who or what is spoken about:
▪︎"the girl who waved" refers to that specific girl who waved, not any other girl.
▪︎"the stone which fell" refers to that particular stone which fell, not any other stone.
In Shaetlan this is done with the invariant marker at, which is a very common strategy worldwide. StE, however, has relative pronouns, and the choice of which to use depends on the animacy of the referent: who(m) refers to animates and which refers to inanimate things. This is very rare worldwide, and also only developed quite late in the English language.