Jean Aitchison wants you to know that "Bob is Petronella's cousin." There's no reason to disbelieve this University of Oxford professor of language and communication.
If, however, you do doubt her, she could probably explain to you how she knows that this is true.
We might, then, accept the idea that language is fairly good at conveying simple pieces of factual information. It's also given to persuasion.
Spatial information, however, is another story.
The English writer Hilaire Belloc once said, "If you can describe clearly without a diagram the proper way of making this or that knot, then you are a master of the English tongue."
Consider the instructions for doing one of the simplest knots, a figure of eight:
1. Pass the end of the rope over the standing part.
2. Take the end under the standing part away from the loop.
3. Bring the end of the rope back up over itself towards the loop.
4. Pass the end down through the loop.
5. Pull tight.
Without its accompanying diagram, this description is difficult to follow (although accurate). In this case, a picture is truly worth a thousand ways.
Aitchison cites the following information from a widely used guidebook to Brazil:
The hike begins... where a paved jogging track runs for 1,200 meters... At the end of the track, pick up the trail on the other side of the cement tank in the tall grass. Follow this trail (always taking the uphill forks) for 100 meters. At the old foundations, some 30 meters above the water, the trail ascends steeply for 60 meters until leveling off on the narrow ridge... The trail to follow is up the far left-hand side ridge. At the base of the rock the trail deviates slightly to the right.
You might agree with Aitchison that these instructions are possibly as clear as language allows - but a map would have made things clearer.
Language is also poor at conveying information about sensation or emotion. "There is no language for pain. Except bad language. Except swearing," writes Martin Amis in London Fields.
"Ouch, ow, oof, gah... Pain is its own language."
The journalist Susie Orbach once spoke of the paucity of language we have to describe emotional life, writing that it could "constrain our capacity to communicate the range and subtlety of our emotional responses."
The poet Byron aptly expressed the failure of language to capture deep feelings when he wrote of his pleasure in pathless woods and the lonely shore, where he could:
"Mingle with the Universe, and feel
What I can ne'er express."