docu: change verb flite

Signed-off-by: rogerdpack <rogerpack2005@gmail.com>

doc/filters.texi

@@ -1144,7 +1144,7 @@ ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose
 @end example
 
 @item
-Make @file{ffplay} speech the specified text, using @code{flite} and
+Make @file{ffplay} speak the specified text, using @code{flite} and
 the @code{lavfi} device:
 @example
 ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'