Shadows of the Past is a continuation of my previous web Comic "Without Magic", in which Twilight was tasked with finding out out "what makes her special as a pony" outside of magic. You do not need to have read Without Magic in order to enjoy Shadows of the past, though some scenes will make more sense if you have.
Please see my disclaimer before reading\commenting, and be aware that this comic contains some darker or more political content that might be not be appropriate for Snowflakes\Millennial, people who are easily triggered, or those who cannot deal with ideas that conflict with their own.
This comic was created using stock resources from Clip Studio Paint and Comipo, and uses some or all of the following components.
Digital Script BB Regular, by Blambot
Death Rattle, by Blambot
Badaboom, by Blambot
DV Brush set for Clip Studio Paint
My Little Pony Brush Set 1.0
Tutorials and Other Resources
Felt Pony Bases
Tutorial: Convert Photoshop brush to Manga Studio
I'd have expect modern Ponish to be some pastiche of the original languages of the three tribes, much like how modern English is Low German with French vocabulary and almost a millennium of drift, simplification, and scattered borrowing from other languages.
So I guess what I'd expect is a language that gets most of its grammar and much of its simplest vocabulary from Earth Ponish, most of the rest of its words (and in particular the ones that are mildly unusual) from Unicornian, a variety of wingtongue calques that are most prevalent in areas like war and weather, and a smattering of esoteric polysyllabic words from one or more languages older than all three.
Colonial rule by a minority, though, never really replaces native languages (barring intensive efforts to break apart non-ruling communities). You can dictate that anyone who needs to interact with the government needs to have a basic proficiency with a given language, which will have the side effect of vocabulary getting borrowed when convenient, but everyone is still primarily going to speak what everyone around them speaks, and the majority don't live in the capital. That goes even more so when the preexisting languages are are small number of widely spoken languages, since then the ruling language isn't even generally needed as lingua franca between different ethnic groups.
So I suppose this would imply that at some point there was a considerable genocide of earth ponies and pegasi, potentially paired with something like Australia's Stolen Generations. That would wipe out Earth Ponish and Wingtongue in Equestria.
I know a lot of native peoples who would disagree with you on that one. Take modern day China where Beijing ruled that all schools in Mongolia and Tibet must use Mandarin Chinese as their language, or when Japan tried to force Korean to speak Japanese during the 1930s. Or when indigenous children were taken away from their families in Canada, Australia and New Zealand were sent to English speaking boarding schools. Or even in Britain where the native Welsh and Scots\Irish languages more or less ceased to exist when power was ceded to Southern England and the dominant dialect there became the main language for both government and commerce.
I'll give you the Celtic languages (although not Scots, which was never very far divergent from English to begin with and is just as much a part of what is called "English" in some parts of Scotland as English is), but it should go without saying that minorities are capable of attempting things in which they will not succeed and that majorities can do things that minorities can't.
And you do know that I already brought up the Stolen Generations and therefore must know about them, right?
That would depend on what you define as being "Scots".
What we think of as being "English" isn't the native tongue of England, it's a dialect that evolved from the languages spoken by germanic tribes that settled in England after the Romans left.
I'm thinking ... G1, given the reference to Megan and Flutter Ponies.
G1 was really dark in that respect, they had an entire story arc about a villain committing genocide against a lost pony tribe.
Still better than Thunder Cats Roar.
Seriously, that cartoon only makes sense if you're familiar with the original 1980s source material, which leads me to question who exactly the intended audience was, and why the writers did that.
And besides.... it doesn't need to take the title of the longest running Cartoon on Cartoon Network. That title remains and solely belongs to Ed, Edd n Eddy ONLY.