Odd Idea

I got this odd idea, though I don't know if it is the least realistic.

I've got to give a scenario:

Quite suddenly (historically that is), in some medieval country, alot of
people abandon
their homes and begin a life on the roads, living in tents or wagons. Most
of these are young
men and women who have been thrown out of their communities ( due to some
odd wave of
superstition, perhaps? ) among these, a sort of language-game evolves, not
intended to transfer
information from speaker to speaker, merely just to make others believe it
actually is a language.

This would go through a few different steps:

1. A Game-language

A phonetically incoherent set of syllabic mumbles, with some
half-recognizeable words
from the everyday languages.

Of course, educated linguists would know this, due to the inconsistense of
the systems.
(of course, the conculture which this happens in evolved linguistics quite
early....)

a certain singing style evolves, where this "language-register" still
survives when the language
has evolved to a true language. (anyone heard KoRn's jibberish-songs? no?
Any conlanger ought
to at least have heard "Twist" on the record "Life Is Peachy", though I
guess most of you don't like
Heavy Metal and such.)

2. A Code

A reason to be able to transfer information in the language appears.

Groups of people will evolve their 'dialects' and begin putting meanings to
words.
Borrowings will appear, but also completely new words. Other languages might
also affect (as foreigners join the bands of "outcasts", perhaps being
outcasted themselves
due to racism?( an eventual conculture of mine would seem quite cruel, when
I come to think of it)).

Distorted borrowings (utbay oremay omplexcay anthay isthay oweverhay)

Simple grammar (pidgin-like), small (but large enough) vocabulary, locally
fixed phonetics...
dialects would be very very different, not to say completely different
languages.

Army sees this as useful and hires them as messengers ( with promises of
some land of their own?
useful due to speakers of the old language in other countries?)

3. A Pidgin / Whatever
(I call it Pidgin / Whatever due to uncertainty as to if this really is a
pidgin.)

The "pidgin/whatever" would be getting native speakers ...
( due to bitterness to the people who banned them from their homes, and
those people's culture ).
And we all know what happens to pidgins when they get native speakers, don't
we?

Now, with the help of some politics (and the fact that in this conworld, I
am pretty close to being a god) I could give this new
people some land (already at point 2 if needed), bring them together, and
see how these pidgin/whatever-languages evolve into one language, mayhap
completely different from the languages of the "Old People" (as they'd refer
to the people from which they originate).
Perhaps their mobile life gets them together enough for the new language to
be somewhat united without an own land? Could they have great meetings where
they came together to celebrate certain things, or even form villages of
their own?

Does such a scenario like this seem at all plausible? I'll create it anyway,
but I'd like to have some opinions, things I could do better, etc.

(Especially the idea of nonsense-song-writing would be interesting,
considering the use of odd phonemes, not even found in the language...)