True, but fashions are a signficant part of vocabulary. Have you read any Raymond Chandler? His novels seem like 80% cliche, 20% normal speech, and they were hugely popular in their era.
Anyway, I still wonder if anyone has begun a long-term study to track syntax/vocabulary shift in response to recent technological change, particularly with regard to comunication tools like email and text messaging. In everyday communication of all forms are sentences becoming shorter and simpler in construction? Are certain grammatical elements disappearing? Is word frequency changing? How is this measured and analyzed?
And at a historical level, can you correlate certain techologies with similar shifts? Sentences were generally much longer and more complex in the 19th century, did the telephone or some other technology change this? How would you guage the historical impact of such inventions on language from a research point of view? How would you "isolate the variables"?
And looking towards the future, what could be the possible *value* of predicting language change in response to current and envisioned technological advance? Could it help us better design future communications technologies to make them friendlier? Is it advantageous to design technologies to minimize semantic shift or maximize it? And finally, what's the answer to that last question from the point of view of different business sectors including the industries that generate change and careers like therapists that manage it? :)