Argument clauses are by definition selected by some higher predicate, and so we expect them to occur only as dependent clauses. However, it seems that they can sometimes occur independently. The discourse chunks in (347) show that this use is discourse-related in the sense that argument clauses can easily occur independently as an answer to a wh-question.

Such examples can of course be analyzed as cases where the context allows omission of the underlined parts of the strings in Ik zei dat Peter hier isI said that Peter is here, Ik vroeg of je nog komt I asked whether you are coming or not, and Ik vroeg wat of je doet I asked what you are doing ... A similar analysis seems possible for echo-questions of the type in (348), where we can assume that the underlined parts in Je vraagt me of ik nog kom? Are you asking me whether I am coming or not? and Je vraagt me wat ik doe? Are you asking me what I am doing? are omitted. We refer to De Vries (2001:514) and Den Dikken (2003a:7) for further examples.

Independently used interrogative non-main clauses are also very common to express that the speaker is wondering about something. The main and non-main wh-clauses in (349) seem more or less interchangeable, although the latter has a stronger emotional load. This emotional load is also reflected in the fact that such independently used interrogative clauses typically contain a modal element such as nu weer: this is clear from the fact that while example (349a') is perfectly acceptable as a neutral wh-question next to (349a), example (349b') feels somewhat incomplete compared to (349b), as marked by the dollar sign.

A similar emotional load can be detected in the independently used declarative non-main clauses in the primed examples in (350); the speaker’s involvement is again clear from the fact that while the primeless examples can be used as more or less neutral assertions, the primed examples emphasize that the speaker expresses a certain wish, is uncertain, feels a certain indignation, etc. De Vries (2001:518) argues that this may be a good reason to consider independently used non-main clauses as constructions in their own right, not in the least because such examples have intonation patterns that differ markedly from those of their embedded counterparts: for instance, (350a') has an exclamation contour, (350b') a question contour, and (350c') allows for various marked intonation patterns.

Independently used non-main clauses may also have highly specialized meanings or functions that their embedded counterparts lack. For example, when used as an answer to the question in (351), the independently used of-clause in (351b) expresses emphatic affirmation: the speaker is replying that he is eager to have the book in question. This use is so common that it would in fact suffice to answer (351) with en of!I sure do!. Embedded of-clauses cannot perform this function, but simply express dependent questions. The independently used embedded question in (351b) have a similar function.

Because a further discussion of the interpretive implications of the independent uses of argument clauses would lead us too deep into the realm of the conditions on actual language use (performance), we will not digress on this here. This topic has received much attention in cognitive linguistics since Evans (2007) under the heading of insubordination: we therefore refer the reader to Verstraete et al. (2012), Tejedor (2013), Van Linden & Van de Velde (2014), and the references cited therein.