That film makes perfect sense to anyone with a big picture awareness of human nature.

The aliens exist on a fourth dimensional level, at the very least, hence why learning their language takes the main character out of synch with her linear life. The aliens state quite clearly that they will need help in the far future, so it stands to reason that the help they will need requires another species capable of fourth dimensional reasoning. Since most humans alive today can't even conceive of fourth dimensional thinking, let alone how to attempt it, no doubt the film comes off a bit confusing.

A strict literal interpretation aside, the film is one huge metaphor for human dysfunction. Linguists have known for some time that people who can bridge linguistic divides are better able to see things from different perspectives, mentally walk in the shoes of people from another culture, as it were. By giving the gift in parts to different human societies, the film is saying that we have to evolve collectively before we can be the help the aliens need. Essentially, it's saying we can't do much good solving our problems if we can't learn to communicate better amongst our own people.