This thread is about the technical aspects of PE's constructed languages. If you don't find the subject interesting, it may be very boring to you.
For PE, I am developing a number of constructed languages (conlangs) to a limited extent to help establish the flavor of the world and the distinct cultures within it. With each conlang, there is (or are) a number of real-world languages used as a starting point. Eld Aedyran is based on Old English with elements of Danish and Icelandic. Vailian is based on a mixture of Italian, French, and Occitan. The ancient Engwythan language (used by the previous residents of Eír Glanfath) is based on Cornish. Glanfathan (used by the current Glanfathan tribes) is based on Old Irish and contemporary Irish.
The orthography of most of these languages is relatively straightforward. A moderately-informed reader will likely mentally read the words and names with 80% accuracy, pronunciation-wise. Players may read the Eld Aedyran name Durnisc as "DUR-nisk" instead of "DUR-nish", but most of the time, they're going to be in the ballpark. If players read about the Vailian consuagli asegia (siege councils), they may not get the stress "right" or hit every consonant cluster correctly in their heads, but they probably won't stumble over the words.
The exception to this is Glanfathan, based on Irish. The foundations of Irish orthography in the Latin alphabet go back over a millennium and had to adapt to using Latin orthography for sounds that probably didn't exist in Latin, like /v/. Irish orthography also uses a set of rules for consonant pronunciation that are based on the surrounding vowels (slender or broad). Irish cased grammar can also mutate words in a way that forces the insertion of additional vowels to maintain their "slender to slender, broad to broad" vowel rules, which means the consonants in between can wind up changing pronunciation as well.
The result is Irish's distinctive "boatload of letters" appearance and unintuitive (to most English-speakers) pronunciation. In contrast, Cornish (another Celtic, but not Goedelic, language) did not develop standard Latin orthography for many more centuries. Its pronunciation is much more intuitive to the uninitiated. Despite the fact that Cornish exists in a different branch of the Celtic language tree, it shares some etymological roots with Irish, but the pronunciation is almost always more intuitive. However, written Cornish is much less distinctive from written Irish.
When you see something written in Irish, there's little doubt what language you're looking at, but the pronunciation will quite often not be "right" in your head. As it applies to the languages, names, etc. in Project Eternity, how much do you care about the intuitive pronunciation of our conlangs?
E.g. in the various Icewind Dale/Dark Elf books, Drizzt's panther is named Guenhwyvar. Most people don't know that the Welsh pronunciation of that name is close to "Guinevere". Does that matter? If you see a name like Dair Bhriste, how important is it to you that the way you pronounce it in your head is the way it is "supposed" to be pronounced?