This was just found in the LvMI archives: Ludwig von Mises speaking on “The Problems of Inflation” at FEE in 1968.
At 41:34, Mises says, “What the individual American… has to realize is that the policy of inflation… makes it impossible for him to organize his working, earning, spending, and saving in such a way that he could provide for the future of his family. This is why inflationary policy is the most radical revolutionary institution in the world.”
At 1:02:03, Mises recommends reading Murray Rothbard’s America’s Great Depression to understand how credit expansion causes the business cycle.
UPDATE: Thanks to Nielsio for putting it on YouTube!