4.7-inch iPhone 6 and the 5.5-inch iPhone 6 Plus
Siri Updated to Respond to Long Questions With Quotes on Brevity
When Siri is given a request that is too lengthy, she will now respond with one of several different quotes that suggest that the user shorten the question. For example, one quote from Thomas Jefferson reads, "The most valuable of all talents is that of never using two words when one will do."
Siri has a range of different quotes in her repertoire, including one from the 1970's television show MASH.
It is unknown when the change to Siri was implemented, but a Reddit thread from last week appears to contain the first known instance of the phrasing, suggesting that Siri's new quoting ability was added within the last week or two.