Solution: As suggested by the title, there are words in the grid whose first letters are silent- 13A, 24A, 39A, 50A, 64A, 68A. If you remove the first letters, the remaining words could be answers for 6 of the down clues. 13A minus A equals ISLE which could be the fill for 8D. 24A minus G = 1D, 39A minus G = 30D, 50A minus W = 52D, 64A minus G = 23D, 68A minus K = 60D. The first letters of the down entries spell KNIGHT. You can add the 6-letter adjective SILENT to fit the theme and the season:) Merry Christmas!