A big warning to users of Block Recognition and Letter Recognition text input: HTC has disabled them in the Sprint WM6.5 ROM update! I confirmed this in a call with Sprint who in turn called HTC.
Although WM6.5 still supports these input modes (called SIPs), HTC's input program ignores the pertinent registry entries and does not present the recognizer options (formerly available as Other Inputs.)
See
http://forum.xda-developers.com/show...99#post5944999 for the most practical workaround I've found. This approach involves writing a Windows shortcut which sets the active SIP to your choice. I then combined the shortcut with keyboard mapping to permit rapid toggling of Block Recognizer mode.