Why would "Axelsson" be written "Ax:son"?
We had an enquiry by a Radio Sweden:
"Hi, a while ago you had a piece on a member of the Ax:son Johnson family. Could you tell me what the : in the name means pls?"
This is the best answer I could find, based on a quick search around.
This use of the colon is unusual, and not linked to common Swedish use of this symbol, which is similar to English use. "Because of this: that happened." "I have two pets: a cat and a dog."
And in Swedish, as opposed to English, the colon can be used to denote the possessive, where a simple "s" cannot be added. For example after an acronym. So the UN General Assembly is "FN:s generalförsamling".
It is also used for ordinal numbers, like 1:a (1st) or 2:a (2nd).
And it is also a traditional way of shortening words. "Sankt" (saint) can be abbreviated to S:t, for example on a sign pointing to a church.
Regarding the Ax:son Johnson family, the Swedish National Encyclopedia says that the founder of the dynasty was simply called Axel Johnson. His son - also an Axel - took the surname Johnson, and also his father's name as part of the surname.
It was the late nineteenth century and he used a mix of the old and new ways of making a Swedish surname. So the son's name was pronounced "Axel Axelsson Johnson". But he chose to shorten the written version, using the traditional method mentioned above. The by-then famous surname Ax:son Johnson was then simply handed down to the next members of the business family.
Other Swedes with similarly shortened names include Melodifestivalen songwriter Thomas G:son, pronounced "Gustafsson".