All human languages have "functional terms" that bracket phrases - words like "if" and "but" in English.

According to Dr Elliott, such terms in any language, are separated by up to nine words or characters.

This limit on phrase length seems to correspond to the level of human cognition - how much information we are able to process at once.

In an alien language, analysing these phrases might make it possible to gauge how clever the authors of the message are.

If they are much smarter than us, there would a lot of words packed into the phrases.

The programme should also be able to break a language up into crucial words such as nouns and verbs, even though their meaning is unknown.