In 1493, a youthful King James IV embarked on a curious experiment, decamping two infant children to Inchkeith island on the Firth of Forth in the care of a mute woman.

The point of the exercise, for the curious monarch, was to determine how the children might learn language while isolated from the rest of the world and if, in its pure state, their utterances were in fact the language of the gods.

Fast forward 500 years or so, and a couple of artists equally curious as King James pick up on what remains a bizarre incident.

Things become even stranger when the artists look into what happened when British troops were stationed on Inchkeith during the Second World War.

A Freedom of Information request lodged with the Ministry of Defence about their own interests in language deprivation casts up some apparently startling material, which the pair determined to make public.

The result of all this is The Forbidden Experiment, the latest dramatic inquiry by performers and theatre-makers Rob Jones and Michael John O'Neill. Collectively known as Enormous Yes, Jones and O'Neill are the latest recipients of The Arches Platform 18 award, which enables and supports the production of The Forbidden Experiment as part of the centre's Behaviour festival before transferring it to the Traverse Theatre in Edinburgh. With reference to feral children, make-believe army regiments, code-breaking and such technical linguistic terms as idioglossia and cryptophasia, the pseudo-lecture structure of The Forbidden Experiment is part detective story and part historical excavation, with what sounds like some decidedly sinister discoveries.

"Inchkeith has always been strategically important," according to O'Neill. "It was used as a place of quarantine for syphilitics and plague victims, then in the Second World War there was a fictional regiment called the British Fourth Army that was a distraction to make the Nazis think there would be an invasion of Norway."

As full of incident and colour as such findings are, they have long been in the public domain, and exactly what new ground O'Neill and Jones' FOI is breaking remains to be seen. "There are elements of it I don't want to go into too much detail about," is all O'Neill will say.

"Most of it was espically boring, with stacks of stuff about shift rotations and things like that. There's stuff about language research and code-breaking, and putting research into practice that has elements of a sinister mystery."

Jones and O'Neill formed Enormous Yes while students at Glasgow University and, inspired by innovative American company, The T.E.A.M. (Theatre of the Emerging American Moment), elected to make what they describe as "theatre to make wrong what once seemed right".

"Our process has been one of going through an extensive research period," O'Neill says, "then developing things through improvisation before I go off and write a script."

This approach has seen Enormous Yes look at libertarian cults, both in the interactive faux seminar of #neednothing, which appeared at the Arches in 2012, and in its sequel of sorts, #sleeptightbobbycairns, which formed part of the Tron Theatre's Mayfesto season.

These were followed by Bonny Boys Are Few, a quasi auto-biographical look at the relationship between sons, fathers and surrogate fathers, which was seen both at the Arches and at the Roundhouse in London in 2013.

What unites these shows is a willingness to fuse fact, fiction and historical mythology in a playful mix of forms that never loses sight of its own artifice as the lines between what is true and what is not become blurred.

"We like to chuck fictional and real things together and see what emerges," O'Neill explains.

"I don't see us in any way making documentaries about our research, but interpreting it in ways that we hope encourages people to question narratives.

"On one level, Bonny Boys Are Few was autobiography, but we pulled it apart with this mix of Irish mythology and real events."

The Enormous Yes takes a reworked version of Bonny Boys Are Few to the Brighton Fringe Festival in May and beyond that, O'Neill, a graduate of both the National Theatre of Scotland's Auteurs scheme and the Traverse 50 new writing initiative, expresses a desire to write something "a bit less mad, something more tightly genre-based".

In the meantime, four people will appear in The Forbidden Experiment, including dancer and choreographer Zosia Jo, while Jones and O'Neill will play versions of themselves.

"There is lots of collapsing of history in the show," O'Neill says, "and Rob's journey and mine to getting the FOI becomes integral to things.

"Characters are paired off through history, and the one thing they all have in common is that they have all lost something and are trying to get it back."

Given the nature of The Forbidden Experiment, one can imagine some concerned overtures from the MOD might have been forthcoming. As it turns out, a surprising radio silence has been the order of the day.

"I have not got any sense that they care," O'Neill says of the MOD. "If it looked like the play was doing anything that they didn't like then they might, but I suspect they have a lot bigger scandals to deal with than an investigation into one that happened in the 1940s."

The Forbidden Experiment, The Arches, Glasgow, April 22-25; Traverse Theatre, Edinburgh, May 1-3

www.enormousyes.com