title_body: How do languages manage to make sense with a free word order? Many of the world's natural languages, and some conlangs, have a free word order, so that the words can be put in any order with it still making sense.
  
  If they can't use word order to indicate the structure, what strategies do they use instead? Have any conlangs used strategies not found in natlangs?
upvoted_answer: It should be noted that in addition to relying heavily on one strategy, it's also possible to mix strategies is various different ways, relying on different strategies to back each other up. For example in Fore(Kainantu-Goroka(TNG), PNG), there is a hierarchy like this, where if each strategy fails, the one lower in the list can be relied on. I'm putting "case" in quotation marks, because the "ergative" case marker in Fore is not really a case-marker as much as it is an often optional and occasionally prohibited derivational marker:
  
  
  Verbal agreement
  Animacy
  "Case"-marking
  Word order
  
  
  Point 2, "animacy" means that referents higher on the animacy hierarchy are interpreted as being more likely to be agents, as such the NPs in a sentence like aebá nanita: yaga: amiye he pig food 3sg:gave_to:3sg "he gave the pig food" can be freely reordered without a change in truth value, despite the fact that the verbal agreement is wholly inadequate to disambiguate the roles of the participants. Only in the few instances where the other strategies fail is word order a primary disambiguative device.
  
  There are some languages where a primary disambiguation strategy is marking on the verb whether such a hierarchy a broken or not, called direct/inverse marking (this can disambiguate situations with two 3rd persons of equal animacy as well by considering e.g. topicality or obviation).