Words with silent letters

To be a good example:

1. the word listed should be very common, if possible

2. the silence of the letters should be "arguable" (through something like a minimal pairs methodology)

The following annotations are generally of the form:

[a|b] in which

a is a word in which the letter in question is not used, but for which the context of the letter, as well as the pronunciation is similar to the given example; the position the letter would occupy in context is denoted by empty <brackets>.

b is a word (sharing some of the environment of the silent example) in which the letter in question is used, and is pronounced.

It is claimed that the presence of both a and b bolster the claim that the word is really "silent", rather than a part of some orthographic environment affecting the pronunciation.
a - aerobic     [<>erosion|pajamaed*]
b - thumb       [plum<>, scum<>, drum<> | humble]
c - yack        [ya<>k] (nick/beatnik)
ch - yacht      [baccara<>t, kumqua<>t, sabba<>t | ichthyology, watchtower, peachtree]
e - gate        [ | agave, toupee (divorce/divorcee)]
g - campaign    [pai<>n | ignite]
gh - through    [you<>, caribou<> | rough, hiccough]
h - hour        [<>our | house]
i - daiquiri    [pla<>que | daisy] (juice/spruce)
j - marijuana   [bivo<>uac | majuscule]
k - sack        [sac<>]   {doc : dock}
l - half        [ha<>fnium, sha<>ft | halt]
m - mnemonist   [<>nemesis | amnesia]
n - column      [plum<> | columnar, glumness]
o - amoeba      [am<>enable | thermoelectric, woebegone]
p - pneumonia   [<>neurosis | cheapness, apnia] (beaucoup)
s - island      [bi<>lateral | Islam, grisly]
t - bouquet     [communique<> | banquet]
th - asthma     [plas<>ma | arithmetic]
u - guild       [g<>ild | anguish]
ue - dialogue   [backlog<>, protolog<> | argue]
w - burrow      [burro<> | frown]
x - doux        [caribou<> | crux] (faux [info<> | auxiliary]
z - chez        [cliche<> | fez]
* it is assumed that, if it were a word, pajamad would be pronounced differently than pajamaed. This lends some support for the notion that the inclusion of the e here affects pronunciation and is, hence, not silent (see also aed.htm).
Please send additions to ddailey@sru.edu