There is a tendency in all of the world’s languages to drop word sounds, especially unstressed syllables. One example is the word for “winter” in Proto-Algonquian, “peponwi”, which developed into “aa” in Cheyenne, after a series of sound droppings1. So, other processes must take place in order to counterbalance this tendency. One such process is grammaticalization, which transforms content words into functional words. Eventually some of these functional words become affixes. That way, while some sounds are eroded, new sounds get incorporated into old words.
Are there other phenomena, besides grammaticalization, that compensate for the loss of sounds in a language?