A study partially conducted by Sandra Weintraub found that this variable impacted the prevalence of routines in language. A study on the impact of this variable found that many speakers have "private meanings" for compound words unrelated to their etymology. Jean Berko Gleason studied the impact of this variable on morphology using nonsense sentences like “this is a man who knows how to rick.” Prestigious features according to this variable’s “graded variation” occur when it is very high or low, and people low in it are also the subjects of the (*) Wug Test. The critical period hypothesis claims that as this variable increases and neuroplasticity declines, language acquisition becomes more difficult. For 10 points, name this variable that causes baby boomers to have a different (10[1])vocabulary from Gen Z. ■END■