@Wiimeiser
 
That’s known as a Doylist explanation. It adds nothing to the world and, in fact, takes you out of the world. The whole point of this is to find a Watsonian explanation, which is one that exists in-universe.

@Homfrog  
This
 
@Background Pony #4D76  
I have a similar language, except half as many clicks and tones (at least in writing). Haven’t decided on grammatical and plural yet, but the word order is OSV (unless the subject is “me” or “you” (“mlp” and “fim” respectively, oddly enough) in which case it’s OVS)… And that’s for simple sentences, don’t get me started on compound sentences, which I’m thinking are agent/patient based.
 
@CocoaNut  
The English is just for convenience. The map is for worldbuilding and the banner was for the sake of the scene.

I think it’s all translated for our viewing experience and they’re not even speaking English

In my Headcanon-verse, due to over 500 years of human contact, English has become the most commonly used language in Equestria. Latin became a language restricted to government, and the Equestrian/Pony language is currently experiencing a revival. Spanish is spoken mostly on the west coast near Los Pegasos because of Spain’s influence in the area.
 
Equestrian/Pony (the very mentioning of that dispute will cause a flame war on Internet forums over there) was written in a logographic alphabet at one point, but in the 1500s, that was changed to a Latin script to “make things easier.” Both scripts are far from easy. First off, the Latin script adds a few letters, such as eth, thorn, and a few Greek letters, and second, there are no less than 22 diacritic marks in use. It’s still better than the old script, though, which had 3166 characters.
 
What makes Equestrian/Pony even more complicated is the grammar. In my HC, you don’t say “She loves him.” You’d say, “Him she loves.” Plus, there are 84 grammatical cases, 8 different tones for vowels that are marked with their own diacritics, 6 click consonants, and not only a singular and plural number, but also a dual and trial grammatical number too.
 
For those who don’t know what grammatical number is, it is why English uses the letter s for multiple things. Now, imagine that if we also used the letter k for 2 things and the letter f for 3 things. You would get Equestrian/Pony’s grammatical number system.

First of all, using pictures for signs could be an indication of a low literacy rate. Given that Equestria is (usually) seen to be at a medieval level of technology, this could be true of their literacy rate. Yes, we’ve seen schools, but it’s entirely possible that these schools are prohibitive to most, either due to low social standing or cost.
 
As far as the writing systems go, I again point you to medieval Europe. Latin was used extremely commonly in writing, especially of the academic variety. It could be that academic writings follow some rule of a standard language across the various kingdoms of Equestria. There could also be a shared language among hoofed animals (such as the horses of Saddle Arabia, cows, sheep, and ponies) and one language exclusive to ponies. Consider the way that Greek was the common language of the Roman Empire for a good long while, with Latin being a sort of “high-class” language and the various regions speaking their own language between themselves.
 
I would say that the hieroglyphs/wingdings are the “high-class” language or else the common language that everyone shares (like Latin in both scenarios), English is the language shared by hoofed creatures, and the weird “written Equestrian” is the pony-only language.

My beard and mustache IS pretty epic, thank you.

Like in our world, there are multiple writing languages. :)
 
Maybe they grow multilanguaged :D

Or it’s different fonts. Similar to our fonts it’s so that the older a font is the more decorated and squiggly it gets.