So, in English, we would instead tend to say, “I am the person who said that Klingon is verb-centric,” using the word “who” as a relative pronoun, instead of as a question word, though in other contexts, this is a question word.

In English, the part of speech of the word who is pronoun. You might use it relatively in clauses to stand in for a stated or implied antecedent (I know who said that), or you might use it to stand in for an answer (Who said that?), but it always works as a pronoun.

In Klingon, we might say {tlhIngan Hol jatlhlu’DI’, wot potlh law’ Hoch potlh puS. jatlhboghpu’ nuv wa'DIch jIH.} That would use the Relative Clause to explain that the first person who said it was me.

Because Klingon has a pair of pronouns that specifically stand in only for antecedent sentences, we can be pretty sure that the question words nuq and 'Iv, which stand in for answers (and hence are also pronouns) can't stand in for antecedents. (And Okrand has said they can't.) Thus, they cannot create relative clauses. I think nuqDaq can also be considered a pronoun.

tlhIngan Hol lughatlh wot 'e' vIjatlh jIH'e' It was I who said that verbs dominate the Klingon language.

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SuStel
http://trimboli.name