According to an experiment by researchers at the University of Rochester and Georgetown University, changes emerge in languages to ensure that they can communicate meaning as precisely and concisely as possible. If languages contain too much redundancy or complexity, they tend to change to achieve a balance between effort and clarity. This may be a reason why similar structures are found in many languages.
The researchers used artificial languages they created to test their ideas and taught them to monoglot English-speaking students. They showed the students images, animations and recordings, and asked them to use the artificial languages to describe what they saw or heard. The languages used suffixes to mark the subject and object of a sentence, and the students tended to use the suffixes to clarify the meaning where it was unclear or ambiguous more than when the meaning was obvious.
One researcher said that “”Language acquisition can repair changes in languages to insure they don’t undermine communication,” and that “new generations can perhaps be seen as renewing language, rather than corrupting it”.
Another researcher commented that contractions, abbreviations and other aspects of informal speech are ways of making language more efficient, though are only used if it’s possible to infer the meaning from the context.