I watched the movie Arrival.
That is the question the movie Arrival asks.
Language affects mindset. Language affects our mood, attitude, and even perspective.
The linear language that we speak makes us have conviction in linearity. So much so that we do not consider the possibility of a nonlinear existence.
Once she appreciates the nonlinear language. Taught of course by those friendly yet spooky aliens, she taps into the non-linearity. Now, travel forward and backward is just that, travel in a direction. No reason one should be more complicated than the other, let alone impossible. That is such a unique take at bread and butter of the sci-fi genre, time travel.
Yet another example of creative prespective.
It is a good movie; you should watch it.