In various Indo-European languages，the positive，comparative，and superlative degrees of adjectives show a gradual increase in the number of phonemes，such as long，longer and longest in English. In the realm of syntax，conceptual and structural complexity tends to go hand in hand. Any modification or elaboration of one meaning-bearing grammatical element by another (as in the process of subordination) leads to the increase of both types of complexity. Let us look at the following examples (Ungerer & Schmid，1996：254)：

（20）a. On the Brighten train from Victoria I met her.

b.On the Brighten train from Victoria I met the girl from next door.

c.Just imagine! Last night on the Brighten train from Victoria I met this fair-haired， fragile，just unbelievably beautiful creature.

Obviously，the pronoun “her”in (20a) is only justified if the person referred to is both unimportant and known，and the reference is expected. ”The girl from next door” in (20b) shows a larger degree of conceptual importance and unexpectedness. And (20c) conveys more information than both (20a) and (20b). The phenomenon that linguistic complexity reflects conceptual complexity is usually called iconicity of complexity.

Iconicity of complexity accounts for our tendency to associate more form with more meaning and，conversely，less form with less meaning. This idea has long been an important aspect of markedness theory. Marked forms and structures are typically both structurally more complex (or at least longer) and semantical/y more complex than unmarked ones. Some scholars even suggest that the amount of linguistic material corresponds to the importance and the degree of predictability of the information processed.