AbstractSentence production is a stage‐like process of mapping a conceptual representation to the linear speech signal via grammatical rules. While the typological diversity of languages is vast and thus must necessarily influence sentence production, psycholinguistic studies of diverse languages are comparatively rare. Here, we present data from a sentence planning and production study in Pitjantjatjara, an Australian Indigenous language that has highly flexible word order. Forty‐nine (N = 49) native speakers described pictures of two‐participant scenes while their eye‐movements were recorded. Participants produced all possible orders of agent, patient, and verb. There was a general preference to produce agent‐initial orders, but word order was influenced by the semantic properties of agent and patient referents (± human). Analyses of participants’ eye‐movements revealed early relational encoding of the entire event, whereby speakers distributed their attention between agent and patient referents in a manner that is different than typically observed in languages that have more restricted word order options. Relational encoding was influenced by the word order that participants eventually produced. The results provide evidence to suggest that sentence planning in Pitjantjatjara is a hierarchical process, in which early relational encoding creates a wholistic conceptualization of an event, possibly driven by pressure to decide upon one of many possible word orders. 379 blackwellopen Cognitive Science Cogn Sci PMC12276719 12276719 12276719 40684369 10.1111/cogs.70087 How Does Speaking A Free Word Order Language Influence Sentence Planning and Production? Keywords: Sentence planning, Relational encoding, Eye‐tracking, Production, Free word order, Australian languages status released display-pdf yes is-in-collection-domain yes is-olf no is-manuscript no is-preprint no is-journal-matter no is-scanned no is-retracted no Revised 2025 May 31; Received 2023 Mar 18; Accepted 2025 Jun 9; Issue date 2025 Jul. 1. Introduction Producing a sentence involves the complex process of mapping a conceptual representation to a linear speech signal via language‐specific grammatical rules (Bock & Levelt, 1994 ; Levelt, 1989 ). An obvious between‐language variable that is likely to affect this process is the grammar of a language. Nordlinger et al., however, suggest that the early relational encoding may be driven not by polysynthesis, but instead by the considerable number of word order options allowed in the language (for converging evidence from Korean, see Hwang & Kaiser, 2014b ). Accordingly, early relational encoding may be due to the pressure to settle on the linear order of constituents to begin the process of linguistic encoding. In the current study, we test these possibilities by adding another Australian language to the literature—Pitjantjatjara (Pama‐Nyungan). Like Murrinhpatha, Pitjantjatjara has been described as having free word order (Bowe, 1990 ). Thus, we hypothesized that in Pitjantjatjara, human referents would be more likely either to appear early in a sentence or be omitted altogether, thus exerting a significant influence on word order variation in the language, and that relative accessibility may play a role in ( 2022 ) observed in Murrinhpatha is due to speaking a free word order language, then we should also expect similarly rapid relational encoding in Pitjantjatjara; that is, we expect an early peak in looks to the agent followed by a rapid peak in looks to the patient, and that the pattern of looks would be influenced by the word orders participants’ produced. Such a pattern would mean sentence planning in the language is also best described as a hierarchical process, and that early relational encoding observed in Murrinhpatha is a consequence of speaking a free word order language. 5B , which suggests a distinction within event apprehension between A‐initial and P‐initial word orders from 400 ms onwards. Determining whether all four word orders differ from each other is a nontrivial process given the complexity of our models (e.g., by computing marginal effects), and so we have chosen to conservatively rely on the posterior probability plots for our interpretation (though see Appendix for posterior probability difference plots). The data are consistent with the suggestion that sentence planning in Pitjantjatjara requires hierarchical planning, which is also consistent with our finding that there was no influence of participants’ first fixation on word order selection. An important issue concerns the apparent difference in relational encoding between Australian languages and other languages with flexible word order, like Basque, Tseltal, and Tagalog. Our method was the same as that used by Norcliffe et al. ( 2015 ) for Tseltal and Sauppe et al. ( 2013 ) for Tagalog. First, it is only one study, although the close alignment between the current data and those of Nordlinger et al. ( 2022 ) for Murrinhpatha points to free word order having a significant effect on speech planning. Second, while the free production method we used has minimal task demands, its experimental nature reduced ecological validity enough to observe a distribution of word orders that differs from spontaneous Pitjantjatjara speech (Wilmoth et al., 2025 ). In this paper, we have reported data to suggest that the ability to freely order sentence elements, a common feature of Australian Indigenous languages, significantly impacts sentence planning in a way that is independent of other typological differences across free word order languages. Specifically, our results suggest that free word order requires a rapid form of relational encoding that may differ from languages that place greater restrictions on word order. This is consistent with the idea that sentence planning in Pitjantjatjara is a hierarchical process, in which speakers rapidly appraise an event and quickly decide upon a word order to produce.