Linear structures of words, sentences, paragraphs, and even books in natural languages could be explained by the property of a human brain to process symbols sequentially, one at a time. Interesting, but sounds and images we process differently, and that is why we can hear at once all musical instruments in the orchestra and we are able to see visual objects at once. For this reason, musical accords are not just sequences of notes and pictorial elements on drawings are not arranged linearly.
Another case is programming languages. Used for human/computer interactions, these languages are designed to present the same information in two different forms: as source codes for humans and as machine codes for computers. While source codes are linear structures - they look almost as texts in natural languages; machine codes are not linear structures - computers do not process machine codes sequentially, in a predefined order.
Furthermore, the language of mathematics is probably the most difficult case. For example, no doubt, the mathematical formula that represents the law of gravity contains some information; however, I am not certain who/what are originators and primary consumers of this information: are they physical objects them-self, a gravitational field around these objects, or it is just my imagination proposes this law? Moreover, it is not even clear how much information does this formula contain: are there few bytes of data that just enough for writing this formula or an infinite amount of information that defines all possible gravitational trajectories in our Universe.