כַּפְכַּף (kafkaf) — sandal, flip-flop

Etymology

The word traces back to the Arabic קַבְּקַאבּ, a wooden clog historically worn in bathhouses throughout the Arab world. The Arabic word itself is of disputed origin: one theory holds it is onomatopoeic, imitating the clacking sound of wooden soles on floors; another derives it from the root ק.ב.ב referring to the belly of an animal (the concave surface on which the foot rests); a third traces it to the root ק.ו.ב meaning to carve in wood; and a fourth argues the word is not originally Arabic at all. The word has been attested in Jewish usage in the Arab world at least since the 9th century CE, appearing in the writings of Eldad ha-Dani, and in a 16th-century responsum by Rabbi Levi ibn Haviv.

Eliezer Ben-Yehuda, who arrived in Jerusalem in 1881 and encountered the footwear in local markets, needed a Hebrew word for it when he translated Jules Verne's Around the World in 80 Days in 1888. Following his stated method of borrowing Arabic words when no Hebrew equivalent existed, he hebraized קַבְּקַאבּ into קַבְקַב. He explained this approach in the preface to his dictionary: "if our language's treasury of roots contains no root from which we can derive the needed word, I turned to its sister Arabic, and did as our ancient sages did." The word spread through the early Hebrew-speaking community and was in common use in kibbutzim by the 1940s.

The shift from קַבְקַב to כַּפְכַּף is a textbook case of two linguistic processes operating together. The first is partial assimilation: the voiced bilabial /b/ in קַבקַב was devoiced by the influence of the adjacent voiceless velar /k/, producing the intermediate form קַפְקַף. This is the same process that turns סַבְתָּא into סַפְתָּא in colloquial speech. The second is folk etymology: speakers who no longer knew the Arabic origin of the word associated it with the Hebrew כַּף (palm of hand, sole of foot), since the sandal is worn on the sole. This caused the initial ק to be reanalyzed as כ, yielding the spelling כַּפְכַּף. The linguist Yitzhak Avinery, responding to a reader's query in the newspaper Al HaMishmar in 1945, noted that the Mishnah itself already attests a variant כפכף alongside כבכב.

For decades both forms coexisted, with traditional prescriptivists insisting that קַבְקַב was correct. As late as 1962, a language column in the newspaper Lamerhav insisted: "the wooden sandal is called קַבְקַב (not 'קפקף' or 'כפכף' as is sometimes pronounced and written)." But by the 1970s כַּפְכַּף had won. Simultaneously, the object itself evolved: the wooden sole gave way to plastic, and the bathroom accessory became a year-round fashion item. By the end of the 20th century, כַּפְכַּף had been normalized in all dictionaries and style guides, while קַבְקַב survives only as a historical term for the wooden original.

Key Quotes

"והן פוסעות פסיעות קטנות ברגליהן הקטנות, נעולות נעלי שש, סנדלי קש, או קבקב עץ מפתחים ומקשטים" — Eliezer Ben-Yehuda, translation of Around the World in 80 Days, 1888

"סנדל-עץ, זה שבסולייתו עץ ועליה רצועת עור, שמו קבקב (לא ׳קפקף׳ או ׳כפכף׳, כפי שמבטאים וכותבים לפעמים)" — Lamerhav newspaper, 1962

"כפכפים בבוקר, בצהרים, בערב - זוהי הצעקה האחרונה באופנת הנעלים לקיץ זה" — Miriam Goren, Davar, April 1973

Timeline

• 9th century CE: Eldad ha-Dani mentions קַבְּקַאבּ in describing the warriors of the tribe of Dan
• 16th century: A halakhic question to Rabbi Levi ibn Haviv involves a servant killed by blows from a קַבְקַב
• 1888: Ben-Yehuda hebraizes Arabic קַבְּקַאבּ to קַבְקַב in his translation of Around the World in 80 Days
• 1945: Reader letter to Yitzhak Avinery asks about proper form; Avinery notes the Mishnah attests כפכף variant
• 1962: Lamerhav language column insists קַבְקַב is the only correct form
• 1973: Davar headline "כפכפים יצאו מתחום האמבטיה" — כַּפְכַּף enters the mainstream fashion vocabulary
• Late 1970s: Wooden soles replaced by plastic; כַּפְכַּף becomes the universal term
• End of 20th century: כַּפְכַּף fully normalized; קַבְקַב relegated to archaic usage

Related Words

• קַבְקַב — original hebraized form; still used occasionally for wooden clogs
• כַּף — palm/sole; the folk-etymological association that drove the spelling change
• סַנְדָּל — sandal; general term for open footwear
• סַבְתָּא / סַפְתָּא — another example of the same devoicing process