Aliens from Ludus

You know a scientist Wade Watts, who discovered a pattern in messages sent by aliens from a planet called “Ludus’’. The language in which the aliens communicate is similar to English. For example, if the world is mississippi, then the word send by them was i4mp2s2. That is, an alphabet followed by a number if the alphabet is repeated, or just the alphabet if it is not repeated. Also, the final e