At the very start of the movie Patton, George C. Scott in front of the giant American flag. Patton gives a speech which becomes iconic for most of the 70s. But, did Patton really give that speech or just something Hollywood came up with?
Well.....yes, but no. Not quite.
The exact wording, the stage (him dripping with medals, the American flag in the background) are fabrications, the spirit of it is true. Patton delivered a series of rousing, profanity-laden speeches to units of the newly activated Third Army in early 1944. He continued to deliver iterations of the speech throughout the 3rd Army formations and up until the commitment of the Army to France.
There's quite a few books that source the speech, or certain iterations of it, and they generally tend to have the same wording as to corroborate one another.
However, there's an open source copy of the speech through the Patton museum of Cavalry and Armor, based in Kentucky.