Hello everyone, first time posting a question. I'm a telegraph historian and I'm struggling to find a reliable and good source to answer this question. Specifically I'm looking for American or Canadian sources that might provide an answer to its origins. A lot of answers I've heard from people online don't make sense to me either and I'll show some of the common answers I've heard and why they don't make sense to me.
"It was more work/more disruptive for the operator to use punctuation than words."
To me this seems incorrect when you realize that the American Morse code for a period was ". . - - . ." and the code for "stop" would have been ". . . - - - . . . ." one requires more physical effort and concentration than the other.
Taken directly from the nbc https://www.nbcnews.com/id/wbna11147506, " People would save money by using the word “stop” instead of periods to end sentences because punctuation was extra while the four character word was free."
This also seems false, though in a less obvious way. For Western Union telegrams rates were somewhat fixed. Telegrams that were 10 words or less were all charged the same, with rate changes based on distance and office location. Any word over that 10 was then charged extra based on the office and distance. While there was seemingly never any hard company rules about how to count punctuation for charging telegrams (in the 1866, 1870, and 1884 Western Union company rulebooks.) The 1884 Western Union rulebook provides a useful example where it states that the figure "44.42" should be counted as 5 words. Meaning every numeral and the "." is counted as a word, the same way "stop" would be. Therefore, so long as you used the "." within your ten words it would be just as "free" as using the word "stop."
"Because the telegraph lacked the ability to use punctuation" or "punctuation code was not invented yet."
As I have already demonstrated in point 1, this is not true, there was code for punctuation. But, it did get me thinking, when was the code for punctuation introduced into American Morse code? Punctuation was not present in Morse's first patent for his code and telegraph in 1840. The full text of his patent only mentions letters and numerals https://patents.google.com/patent/US1647A/en . Sadly, this is where my research got stonewalled. I could not find a complete and accurate history of the evolution of American Morse code that included any mention of the addition of punctuation past Morse's original patent. However, I am quite sure that for most of the telegraph's history punctuation was an option. I have a telegraph textbook from 1883 that includes code for punctuation, the book "The Telegraph in America" from 1879 also includes code for punctuation, and a Canadian telegram from 1847 has what to me looks like a period at the end of the first line. I also think what looks like the capitalization of the "S" in "She" at the beginning of the second line also supports my reading (https://tinyurl.com/mthwdcax).
"Because during WW1 governments and militaries wanted greater clarity and security in sending, so they used STOP instead of periods to avoid ambiguity."
I don't know where exactly the originator of this is from, but again this explanation kind of admits that code for punctuation had already existed. I find a lot of people citing a booklet "How to Write Telegrams Properly" from 1928, and it is the earliest example I've found for this explanation's origins. I haven't found any sources making similar claims. Still, this explanation does not make sense to me. The code for STOP (". . . - - - . . . .") is just as likely to be misinterpreted as the code for a period, if not more so as the American Morse code for "O" was a confusing "- -" essentially two dashes with a space between them that's smaller than the space between words. Giving this explanation the benefit of the doubt, let's say militaries preferred having STOP written out because it was harder to miss than a period? That still leaves the question of how and why it would be adopted popularly by people after the war.
In short, I don't know what the origins of using STOP is for telegrams. I think it's likely a form of telegraphese that originally spread through popular culture and public ignorance about the telegraph after wider use of the technology in the 1920s and 30s and it did not come from the telegraph industry. Or, it could have come from the telegraph industry with the introduction of new printing telegraph machines in the early twentieth-century and perhaps they had a technical limitation requiring the use of STOP which previous Morse telegrams that were typed or handwritten did not need to do. However, I cannot find sources to strongly support either claim. It does seem to me like the origin of STOP is from the twentieth-century, post-WW1 specifically, and not from the nineteenth-century, though I'm open to being proven wrong.
If any military historian knows anything about the use of the word STOP in war telegrams and has any evidence to point towards its use in confidential or government business I'd be interested to see it. If any other historians know of STOP's wider use in telegrams or think I may have made a mistake or error in my assessments of these common explanations I'd be happy to hear them out. I would prefer sources for any answers provided if possible. Thank you very much.
First of all, you are correct that punctuation was added to Morse code almost immediately. As early as January 31, 1848, Morse’s collaborator James Vail recorded that he had developed a punctuation system. But as you mention, this is not 1844 when Morse began using a dots-and-dashes code. The 1844 system was transported to Europe lacking punctuation (along with many other flaws), and according to a German history of Morse code, at first, full stops were written out as the word "Punkt" literally meaning “period” or “dot”. But this only lasted a few years. The code for period was added to German Morse code on July 1, 1852, at a meeting of the Deutsch-Österreichischer Telegraphenverein (Austrian-German Telegraph Union).
This seems to leave only a few years in the 1840s and 50s when telegraph operators might have had to clumsily spell out full words for punctuation. However, it does raise an interesting issue. The German system was quickly applied to London. But it was never widely used in America, where it was called the “continental” system. Gradually the “continental” system spread to various colonies and Australia as well, and it was recognized that America was the odd one out, but Americans stuck to their system. So, by the time of World War I, Britain and the US were standardized on two different sets of punctuation. A radio engineer wrote in 1914:
I may state that I am a strong champion of the American Morse code for radio work, altho I am compelled to bow to the overwhelming majority in favor of the Continental Morse. The necessity for a universal radio code is, of course, apparent to all.
While I also do not find any sources other than "How to Write Telegrams Properly" explicitly saying that STOP arose in World War I, we might posit a scenario where a lot of telegrams are being rapidly sent between American and British operators, and there is a sudden need for a less ambiguous way to indicate punctuation...
As you note, many of the secondary sources on the Web point to a 1928 guide by Nelson Ross on How to Write Telegrams Properly. However, nearly all of them point to a web page not updated since 2004, which doesn't seem to have any live hyperlinks within it, and I haven't yet found the booklet's actual text online. As it's still a year from copyright safe harbor, the booklet doesn't yet appear to be on archive.org or Google Books—though it appears I could actually buy a copy of it via bookfinder.com.
I did find this webpage which purports to quote from the booklet
"If you do not intend to stipulate that marks of punctuation be transmitted, write your message without punctuation and read it carefully to make sure that it is not ambiguous. If it seems impossible to convey your meaning clearly without the use of punctuation, use may be made of the celebrated word "stop," which is known the world over as the official telegraphic or cable word for "period."
I was a participant in a forum discussion from 2002 on this very topic, which does quote extensively from a different guide, and may prove useful to you.
There are many examples visible online of telegrams containing periods and other punctuation marks—but there are also a few that can be found containing the word STOP or equivalent. In the two decades since the aforementioned forum discussion, I've come to think the spelled-out word is primarily a dramatic trope to emphasize what type document the actor is reading from, with some real-life examples, particularly the oft-mentioned military messages, to be found. This 1899 instruction manual makes no mention of the practice. By the 1920s, commercial message traffic between telegraph offices in cities of any size was handled by automatic printing telegraphs or teletypewriters, which would have had little need to take such measures for clarity.