All of/on a sudden

An editor used the phrase 'all on a sudden' in a report, but another, who was asked to read it for the second time, changed it to 'all of a sudden,' as he found it in the dictionary lying on the table. Every student inside seven or eight years in his schooling in Bangladesh at a point in had to learn the phrase, 'all on a sudden,' along with 'all of a sudden,' both of which mean 'suddenly.' The matter did not end there. Only that the OALDCE has ceased to include 'all on a sudden' was settled at the moment.

A Google search showed there is disagreement among the purists on if it should be 'all of the sudden' as in 'all of a sudden,' there is an indefinite article before an adjective, which is not congruent with the rules of the English language. According to online sources, the phrase was first used in the language in 1558 as 'upon the soden,' which became 'of a sudayn' in 1596 and 'all of a sudden' in 1680. It clearly shows that 'upon the sudden' made its way to 'all of a sudden.' But is 'all on a sudden' wrong? No, it is not.

Towards the end of the 19th century, writers of repute used both 'all on a sudden' and 'all of a sudden' in the same text. Both the forms are correct. According to practical dictionaries, 'all on a sudden' is archaic, and 'all of a sudden' is on its way of being archaic. The Authorised Version Bible does not contain any of them; it has used the word 'suddenly' instead, which now seems to be in currency.

The Concise Oxford Dictionary suggests (all) of/on a sudden and Arthur Conan Doyle towards the 1890s, on several occasions, used 'of a sudden' as in '...yet when Alleyne had passed him, of a sudden out of pure devilment, he screamed out a curse at him.' (The White Company)

The unabridged Oxford also lists on/upon a/the sudden, at a/the sudden and even in a sudden, which are obsolete variants.