These three words share a fascinating silent consonant — the silent “b” in thumb, the silent “g” in phlegm, and the silent “ch” in drachm — and each of those silent letters is a kind of fossil, a remnant of an older pronunciation that speech gradually smoothed away while spelling stubbornly preserved it. This phenomenon, sometimes called a “ghost letter,” reflects one of the great tensions in English orthography: that written language tends to be conservative and slow-moving, clinging to ancestral forms long after the spoken tongue has moved on. The b in thumb echoes back to Old English þūma, where the labial consonant was audible; phlegm retains the Greek spelling of φλέγμα even as Latin and then English mouths softened it; and drachm carries the ghost of the Greek δραχμή, a word that crossed into English through commerce and medicine with its spelling more or less intact but its sound thoroughly naturalized.

Beyond orthography, these three words also paint a remarkably vivid portrait of the ancient Greek world’s influence on Western thought. Drachm is a unit of coinage and weight — silver currency clinking through the Athenian agora — and speaks to commerce, trade networks, and the long reach of Greek economic systems into Roman, Arabic, and eventually English apothecary measurement. Phlegm comes laden with the entire edifice of Galenic humoral medicine: the four humors that governed European medical thinking for nearly two millennia, where phlegm embodied cold, moisture, sluggishness, and the lymphatic temperament. Thumb, by contrast, is resolutely Germanic and earthy — a word for the body’s most practical digit, used for pressing, gripping, and judging. Together, the three words sketch a miniature history of how English was built: Greek learning filtered through Latin scholarship meeting the blunt physicality of Anglo-Saxon daily life, all frozen together in spellings that quietly remember what the voice has long forgotten.