Norway has decided by act of parliament how its language should be pronounced exactly once. It happened in 1951, it concerned the number words, and the initiative came from the state telegraph authority.
The reason was practical. Phone numbers in Oslo had been extended from five digits to six, and the telegraph board had measured that people wrote down markedly fewer errors when numbers were spoken in the same order they are written – tjuetre, trettifire, syttiåtte rather than the inverted tre og tyve, fire og tredve, åtte og søtti, which is how Norwegian, like German and Danish, had always done it. Parliament voted unanimously on 22 November 1950, and the new counting system took effect on 1 July 1951.
Seventy-five years later there is no longer a person taking the number down. There is a machine. And it has inherited precisely the problem the telegraph authority set out to remove.
Both counting systems are still in use
The 1951 decision did not abolish the old system. It remains common in everyday speech, particularly among older speakers.
For a voice agent that means seksogtretti and trettiseks are the same number, that syv and sju are the same digit, and that older forms like tyve and tredve turn up in real calls even though they are not standard written Norwegian.
Each of those is easy enough to handle on its own. What makes it hard is that both systems can appear in the same sentence, from the same person, inside the same number. Someone reading out eleven digits will often switch rhythm halfway through without noticing.
A number is not a number. It is a field.
The single most useful thing an agent can know when it hears digits is what the digits are supposed to be.
Norwegian identifiers have fixed lengths, and several of them carry built-in check digits:
| Identifier | Digits | How it is usually read aloud |
|---|---|---|
| Postal code | 4 | One by one, or as a single four-digit number |
| Phone number | 8 | In pairs |
| Company registration number | 9 | In threes |
| Bank account number | 11 | Four, two, five |
| National identity number | 11 | Six, then five |
If the agent knows it is filling the field "company registration number", it also knows the answer has to be nine digits, and that the last one is a check digit computed from the eight in front of it. At that point the transcription is no longer a guess that has to be accepted. It is a guess that can be rejected. Account numbers and identity numbers carry equivalent checks.
This is a cheap mechanism, and it is cheap precisely because it has nothing to do with audio. The field does the arithmetic, not the ear.
The line strips out what separates the digits
Ordinary telephony carries roughly 300 to 3400 hertz. Everything above that is gone.
That is a sensible trade for speech in general and a poor one for digits. Much of the energy that distinguishes an s-sound from an sh-sound sits above 3400 hertz, which is why over a phone line the Norwegian seks and sju sound less different than they do in a quiet room. In an ordinary sentence this costs nothing, because the rest of the sentence carries the meaning. In a run of eleven digits there is no such help. Every digit has to stand on its own.
It is also why digits are the part of a conversation that degrades most when a system leaves the lab. A demo tells you little about what the agent does for real, and for numbers the gap is at its widest: the demo runs over broadband, on a good microphone, in a quiet room.
