You will be given a definition of a task first, then some input of the task.
In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.

Proto-Indo-European language ( PIE ) is the ancestor of the Indo-European languages .
Output:
Proto-Indo-European ( PIE ) is the linguistic reconstruction of the ancient common ancestor of the Indo-European languages , the most widely spoken language family in the world .