Why does French have that eccentric number system for seventy, eighty and ninety? The Belgians, Canadians and the French-speaking Swiss all have reasonable words for these numbers (septante, huitante or octante and nonante), which any French person will (2024)

Why does French have that eccentric number system for seventy, eighty and ninety? The Belgians, Canadians and the French-speaking Swiss all have reasonable words for these numbers (septante, huitante or octante and nonante), which any French person will grudgingly understand.

Paul Reilly, Tylers Green

• The number system in French is derived from that used in Gaulish, the Celtic language spoken in France before the modern Romance language drove it out. If you look at the counting systems of modern Celtic languages like Welsh or Scottish Gaelic, you'll see a similar pattern to that in French. In Gaelic, for example, multiples of twenty are used as a base for counting (the so-called 'vigesimal' system). Twenty is 'fichead', forty 'dá fhichead' (lit. 'two twenties') and so on up to eighty 'ceithir fichead' ('four twenties', like French 'quatre vingt'). The intervening multiples of ten (fifty, seventy, etc.) take the form 'n twenties plus ten'. Thus, ninety is 'ceithir fichead is a deich' (four twenties and ten, exactly like French 'quatre vingt dix'). Many modern varieties of French have done away with the vigesimal system altogether, instead using the 'n-ante' forms used in Canada, Belgium and Switzerland; how long the French of France will hang onto the vigesimal system for numbers above sixty is anyone's guess. In Scotland, children learning Gaelic are now taught a simplified decimal system (e.g. seachdad = 70, ceathrad = 40) alongside the vigesimal numbers - understandable when, for example, the number ninety-nine is 'ceithir fichead is a naoi deug' in the older system.

  Dominic Watt, Department of Linguistics and Phonetics, University of Leeds

• The Danes have a similar system for 60 and 80 (60 is tres or three twenties). However, when writing cheques, they write seksti or six tens.

  Les Stennett, Preston, Lancashire

  See Also

  Form DS 82 Step 10 Most Recent Passport Book or Passport Card

• It is not such an unusual way of counting if we think of the old English "score" - a man's lifespan is traditionally three score years and ten, for example. Perhaps, when talking of larger numbers of, say, animals, it may have been easier to visualise three or four groups of twenty than a single batch of sixty or eighty.

  Adrian Deere-Jones, Glynneath, West Glamorgan

• These numbers in French and certain old Celtic languages derive from a time when people counted using a base of twenty. I believe they counted using not only their fingers but also their toes, hence a base of twenty was used.

  Dave Dohrn, Abertridwr, UK

• Living in Quebec, I can testify that the French-Canadian dialect is just as "unreasonable" as French in France. 99 cents in Quebec is still quatre-vingt dix-neuf sous.

  Luke Andrews, Montreal, Quebec Canada