Syntax
How do you know what order words should be in when you speak or write sentences? You know how to order words because you learned syntax: the rules that specify how words should be ordered in a sentence to make the sentence meaningful. Of course, these rules vary according to language (English is different than Russian, for example). For example, if you want to tell someone that you ran to the store, you know to put the verb "ran" before the noun "store" to form the sentence "I ran to the store" as opposed to saying "I store ran".