switch reference in English

English has no switch reference system. No affix, pronoun or connective states that the subject of a dependent clause is the same as, or different from, the subject of the clause it depends on. Where the identity matters a speaker relies on an overt pronoun, on the reflexive series, or on context, and where none of those resolves it the sentence is simply ambiguous, which a language with this marking would not permit.

One candidate might have qualified and does not. A nonfinite complement and a participial adjunct both take their subject from the main clause rather than expressing one, so a clause built with an infinitive is understood with a single subject while the corresponding finite complement can have two. That alternation follows from the fact that a nonfinite clause has no subject position to fill and must find its subject elsewhere, so it is a consequence of how the clause is built rather than a marking of the relation between two subjects. It also fails the coverage test twice over: the interpretation of a participial adjunct is not fully determined by the rule, which is why a dangling participle is a recognised error rather than an ungrammatical string, and the option is unavailable in most of the contexts where the relation might need stating.

Marking of this kind is required even where the identity is already unambiguous, and nothing in this language is. The absence recorded here is an assertion about the language and not a gap in the description of it.