Chapter 9 discusses the SO preference observed in the domain of language production, i.e., that sentences with SO orders are more frequently produced than sentences with OS orders in many languages. Although the language production mechanism is often assumed to be universal, the range of languages investigated so far is typologically quite limited. We conducted a sentence production experiment with a picture description task to clarify word order selection in Kaqchikel. In this experiment, participants verbally described the target pictures with a simple sentence. Speakers of Kaqchikel had a general preference for producing the SVO order over the VOS order. This is consistent with the prediction of the UCV, but not with that of the IGV. Therefore, the SO word order might be a universal preference in sentence production, which is in line with the results of previous studies.

Chapter 2 sketches aspects of the grammar of Kaqchikel relevant to the discussions in the subsequent chapters. Kaqchikel is a Mayan language spoken in Guatemala. It is a head-marking and morphologically ergative language in which subjects and objects are not overtly case-marked for grammatical relations. Rather, grammatical relations are obligatorily marked on predicates, e.g., a verb with two sets of agreement morphemes, one set for a transitive subject and another for a transitive object and an intransitive subject. The word order of Kaqchikel is relatively flexible, and all of the logically possible six word orders are grammatically allowed. Among these, VOS is considered the basic word order of Kaqchikel by many Mayan language researchers.

The experimental studies on Kaqchikel reviewed so far suggest that the cognitive load during sentence comprehension is primarily determined by grammatical processes operating on linguistic representations, whereas word order selection in sentence production more faithfully reflects conceptual processing at the stage of event apprehension and preverbal message construction. In particular, agent-first orders are likely to be selected over others because of the conceptual saliency of agents. If this conjecture is on the right track, we would expect that the cognitive load during sentence production is higher for SVO sentences than for VOS sentences because the production of a sentence surely includes, as its central part, the construction of linguistic representations, and the grammatical processes involved in this are presumably similar to those involved in the comprehension of a parallel sentence, although there may be some differences. Chapter 10 reports on an experiment to verify this prediction. The results of this experiment support the conclusion that, although Kaqchikel speakers preferentially use the SVO word order because of the saliency of the subject, SVO sentences require more processing resources than VOS sentences both in comprehension and in production.

Chapter 12 considers the syntactic structure of Kaqchikel sentences in more detail. There are multiple syntactic routes to the VOS order. Different VOS languages may have different syntactic structures. There are two major proposals regarding how Mayan VOS word order is grammatically obtained. We propose in this chapter that Kaqchikel, and possibly Chol as well, derive the VOS order through a right-specifier route, rather than a predicate fronting route.