Iain/John interchangeable

[Al99]

I believe Iain and John are interchangeable, particularly in Scotland.
Does anyone know why?
Are there other names that are interchangeable?

[BumbleB]

Iain is the Scottish Gaelic spelling of John.

I'm sure there are others.

[Little Nell]

I have Daniel/Donald as the interchangeable names in one of my Scottish families.  It is another example of Gaelic names where the pronunciation has led to the other.

Elizabeth and Isabel are potentially also interchangeable.  Ishbel or Elspet are Scottish variants.  Isabel(le) was common in medieval French, while Elizabeth was perhaps more widely used in England.

Nell

[Elwyn Soutter]

Roderick = Ruairidh

Mary = Mairi

[Al99]

Iain and John don't look or sound alike!

[Little Nell]

But pronunciation over time changes and we should not forget this.  That is how Donald could become Daniel, because of the the way it sounded.  And then how someone wrote that down.

There is no J or a J sound in Welsh: Sion/Sean was the Welsh equivalent of John.  Jan is the Dutch and other European languages equivalent of John.  The J sounds like 'y'.

And to quote Sean Connery aka Dr Henry Jones in the famous film: "Jehovah in Latin begins with 'I'  "and was pronounced in Hebrew as Yahweh.

Nell

[Andrew C.]

Iain and John don't look or sound alike!

In Scotland J rhymes with I not with May as I believe the letter J developed from I, so you can see a link from Jan to Iain., also Ivan, Ivan or Ieuan. The origins of John is the Greaak Ioannes developing into Johannes, Johann John etc.

I know three generations of John, grandfather known as Jack father John and son Iain but all John on their birth certs.

[Forfarian]

Janet/Jessie is probably the most common. I've never been able to find out how and why Jessie became regarded as an equivalent to Janet, because their derivation is unrelated, but when I mislay a Janet, I very often find her as Jessie, and vice versa.

Jane/Jean and variants

Jane/Jean and Janet are also often said to be interchangeable, but in my experience this is unusual. I have found more families with both a Jane/Jean and a Janet than I have ever found instances of a Jane/Jean turning up as a Janet.

Hector/Eachainn (no idea why)
Margaret/Marjorie and variants
Peter/Patrick
Elizabeth/Betsy .... Betsy/Beatrice .... Beatrice/Elizabeth
Ann(e)/Nan .... Nancy .... Agnes

Elspet is the Scottish spelling of Elizabeth, and Isabella is originally the Spanish version of Elizabeth, but over time that equivalence has been lost and it's unusual now to find an Elizabeth as Isabella or vice versa.

For umpteen more examples, and some explanations, see https://whatsinaname.net/

[Forfarian]

Iain and John don't look or sound alike!

No, they don't if you are fixated on the idea that a particular letter squiggle on paper or in print is only ever pronounced as it is in English regardless of which language the word or name comes from.

(Even though a letter squiggle at the end of an English word doesn't always sound the same as it does at the end of a word. Think of the sounds given by a speaker of English to the letter squiggle y in the word young and in the word happy.)

But that isn't the case. In many European languages the initial letter squiggle j is pronounced as the initial letter y is in English. The names Jan and Johan in German, Dutch etc sound like Yan or Yohan.

Iain pronounced by a Gaelic speaker also sounds as if it begins with a sound not dissimilar to initial y in English.