When a word has "silent" consonants, it's usually (always?) an indication that sometime in the past, the consonant was pronounced. In other words, English was once spelled phonetically, and in some cases, we kept the old spelling and changed the pronunciation.

I suppose that applies to the L in "could" and "would".

Try getting your tongue around that.

I have seen some old song texts that used the spelling "cou'd" and "wou'd"—to remind people, I suppose, that they weren't supposed to pronounce the L.