Question

Underline the silent letters in each of the words. Example: Walk.
comb, adjective, sign, knee, gnaw, autumn, saw, wrap, pneumonia, castle

Answer 1

Walk - L, Comb - B, Adjective - E, Sign - G, Knee - K, Gnaw - G, Autumn - N, Saw - W, Wrap - W, Pneumonia - P, Castle - T....

Answer 2

The alphabets which despite remaining in a spelling often stays inactive.

This no-sound letters are called silent letters.

Out of the list, walk (l silent), sign(g), knee(k), autumn(n), wrap(w), and castle(t).

The alphabets in the bracket are not sounding in the spelling hence they are called silent letters in those specific words.

For example in the spelling walk, the sound of la is absent, L is the silent letter.