Argument clauses are selected by some higher predicate by definition and we therefore expect them to occur as dependent clauses only. Nevertheless, it seems that they sometimes can occur independently. The discourse chunks in (338) 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 in which the context allows omission of the underlined parts of the strings in Ik zei dat Peter hier is'I 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 (339), where we may 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 (2003:7) for more 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 (340) seem more or less interchangeable, although the latter has a stronger emotional load. This emotional load is also reflected in that such independently used interrogative clauses typically contain some modal element like nu weer: example (340a') is completely acceptable as a neutral wh-question; example (340), on the other hand, feels somewhat incomplete and is certainly not construed as a neutral wh-question, as is marked by means of the "$" diacritic.

A similar emotional load can be detected in the independently used declarative non-main clauses in the primed examples in (341); 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 makes a certain wish, is uncertain, feels a certain indignation, etc. De Vries (2001:518) argues that this may be a good reason for considering independently used non-main clauses as constructions in their own right. Another reason he gives is that such examples have intonational patterns that differ markedly from those of their embedded counterparts: for instance, (341a') has a typical exclamation contour, (341b') a question contour, and (341c') allows 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 (342), the independently used of-clause in (342b) 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 (342) with en of!'I sure do!'. Embedded of-clauses cannot perform this function, but simply express dependent questions.

Because discussing the interpretational implications of the independent uses of argument clauses would lead us into the domain of the conditions on actual language use (performance), we will not digress on this. This topic has received some attention in Cognitive Linguistics since Evans (2007): we refer the reader to Verstraete et al. (2012), Tejedor (2013), Van Linden & Van de Velde (2014), and the references cited therein.