Thesis: All processes or formalisms that resemble arithmetic are identical to arithmetic,
or else unthinkably complicated and arbitrary.
This is why we can communicate perfectly about numbers. 
Xenolinguistics is the scientific study of languages of non-human intelligences. Publications in this field tend to be speculative as few people have made the claim to have understood an alien language, at least not reliably.
- Regis, Edward (1987). Extraterrestrials: Science and Alien Intelligence. Cambridge University Press. ISBN 0521348528.