Look at two or three given words and decide which letter is silent in both or in all three Which letter is silent in limb, and lamb? (L-I-A-M-B) Which letter is silent in knee, know, and knot? (T-N-K-O) Which letter is silent in ghost, heir, and hour? (G-R-H-E) Which letter is silent in raspberry and cupboard? (B-P-S-R) Which letter is silent in wrinkle, wreck, and wrist? (K-R-W-I) Which letter is silent in autumn, solemn and column? (M-N-O-L) Which letter is silent in castle and nestle? (C-L-T-S) Which word has a silent B? (doubt-rubber-plumber-robes) Here's a tricky one: In the word phone, what sound do the letters PH make? (a J sound-a P sound-a F sound-an H sound)