We often claim the new education system produces poor spelling but who is to say they were any better back on the 1940s. Also how would a newspaper be able to check the spelling for a base or battlefield that was probably not on even on an atlas map. I see no value in having 'official' names that are only out by one letter.
I have always assumed that Guadalcanal was an anglicised form of the original Spanish name Guadalcanar, and as you say the latter was used pretty extensively during the earlier war period, less so in latter part. The British Solomon Islands (or BSIP, for British Solomon Islands Protectorate) were riddled with Spanish names, and many of these had Anglicised versions, so these are not mistakes as such, just at the whim of the writer, or conventions of commanders or newspaper editors. Then there are the local (native) names which could be spelled differently, seemingly based on what the listener heard, or thought they heard. Archives NZ has in its stored records has an official publication (British or American?) with the title along the lines of "Place names in the British Solomon Islands" which I will have to study one day. This might also point out the problems of non-standardised spellings, and conventions followed, if any! Ondongo/Ondonga is probably one such variation in spelling. I also notice that some Japanese WW2 names for certain geographic features around Rabaul seem to have remained in circulation, particularly for some of the volcanoes, some of which have local/English (as in "South Daughter", Mother") and Japanese names. There are also some American WW2 names which have stuck, or at least I think they have, such as "The Slot", as well as the island located near where PT-109 was cut in half (Plum Pudding Island perhaps?) David D
I thought at first that Guadalcanar may have come from an OCR misread of old documents but searching further I found out that Guadalcanal is a Spanish place name and when spoken in the local accent appears to the English ear as ending in ‘canar” It looks like this was the version that was transcribed back in the 16th century and in common use afterwards. It may have been as late as 1932 under the British Protectorate that it was standardised to “Guadalcanal”.
Likewise Ondongo and Ondonga were just different interpretations of the local dialect. I’m not sure how it was spelt on earlier maps but I doubt if there was any signpost there before the Seabees arrived.
From Wiki: Sometimes referred to as Guadarcana, Gguarcana, Guadalcana, and Guadalcana. Named after a town in Andalusia, Spain, the differences are the different pronunciations of its name in that part of Spain. Guadalcanal was officially confirmed as it's name by the British in 1932. And some people get all worried about an H in Whanganui. isc
ps, maybe the reporters were using an old Atlas to check the spelling.
Espiritu Santo in Vanuatu has several itterations, such as Santo and Santos, and in wartime documents you often find it listed as NZAPO 366, but all are more or less the same place. Emirau in modern maps is usually spelt Emira. Davis D