The following is an excerpt from Thinking in Numbers: On Life, Love, Meaning, and Math, by Daniel Tammet, out now from Little, Brown.
Ask an Icelander what comes after three and he will answer, “Three what?” Ignore the warm blood of annoyance as it fills your cheeks, and suggest something, or better still, point. “Ah,” our Icelander replies. Ruffled by the wind, the four sheep stare blankly at your index finger. “Fjórar,” he says at last.
However, when you take your phrase book—presumably one of those handy, rain-resistant brands—from your pocket and turn to the numbers page, you find, marked beside the numeral four, fjórir. This is not a printing error, nor did you hear the Icelander wrong. Both words are correct; both words mean “four.” This should give you your first inkling of the sophistication with which these people count.
Icelanders have highly refined discrimination for the smallest quantities. “Four” sheep differ in kind from “four,” the abstract counting word. No farmer in Hveragerði would ever dream of counting sheep in the abstract. Nor, for that matter, would his wife or son or priest or neighbor. To list both words together, as in a textbook, would make no sense to them whatsoever.
This numerical diversity applies not only to sheep. Naturally enough, the woolly mammals feature little in town dwellers’ talk. Like you and me, my friends in Reykjavík talk about birthdays and buses and pairs of jeans but, unlike in English, in Icelandic these things each require their own set of number words.
For example, a toddler who turns 2 is tveggja years old. And yet the pocket phrase book will inform you that “two” is tveir. Age, abstract as counting to our way of thinking, becomes in Icelandic a tangible phenomenon. Perhaps you too sense the difference: The word tveggja slows the voice, suggesting duration. We hear this possibly even more clearly in the word for a 4-year-old: fjögurra. Interestingly, these sounds apply almost exclusively to the passage of years— the same words are hardly ever used to talk about months, days, or weeks. Clock time, on the other hand, renders the Icelander almost terse as a tick: the hour after one o’clock is tvö.
What about buses? Here numbers refer to identity rather than quantity. In Britain or America, we say something like, “the No. 3 bus,” turning the number into a name. Icelanders do something similar. Their most frequent buses are each known by a special number word. In Reykjavík, the No. 3 bus is simply þristur (whereas to count to three the Icelander says “þrír”). Fjarki is how to say “four” when talking buses in Iceland.
A third example is pairs of something—whether jeans or shorts, socks or shoes. In this case, Icelanders consider “one” as being plural: einar pair of jeans, instead of the phrase book einn.
In English, I would suggest, numbers are considered more or less ethereal—as categories, not qualities. Not so the smallest numbers in Icelandic. It is as though each corresponded to a delicate nuance of color. Where the English word red is abstract, indifferent to its object, words like crimson, scarlet, and burgundy possess their own particular shade of meaning and application.
We can only speculate as to the reason why Icelanders stop at the number five (for which, like every number thereafter, a single word exists). According to psychologists, humans can count in flashes only up to quantities of four. We see three buttons on a shirt and say “three”; we glance at four books on a table and say “four.” No conscious thought attends this process—it seems to us as effortless as the speech with which we pronounce the words. The same psychologists tell us that the smallest numbers loom largest in our minds. Asked to pick a number between one and 50, we tend toward the shallow end of the scale (far fewer say “40” than “14”). It is one possible explanation for why only the commonest quantities feel real to us, why most numbers we accept only on the word of a teacher or textbook. Forty, to us, is but a vague notion; 14, on the other hand, is a quantity within our reach. Four, we recognize as something solid and definite. In Icelandic, you can give your baby the name “Four.”
This profusion of Icelandic words for the purpose of counting appears to be an exception to the rule. Many of the world’s tribal languages, in contrast, make do with only a handful of names for numbers. The Veddas, an indigenous people of Sri Lanka, are reported to have only words for the numbers one (ekkamai) and two (dekkamai). For larger quantities, they continue: otameekai, otameekai, otameekai ... (“and one more, and one more, and one more ... ”). Another example is the Caquintes of Peru, who count one (aparo) and two (mavite). Three they call “it is another one”; four is “the one that follows it.”
In Brazil, the Munduruku relay quantity by according an extra syllable to each new number: one is pug, two is xep xep, three is ebapug, and four is edadipdip. They count, understandably, no higher than five.