This is excellent topic, Alan. Thanks for coming up with it!
First couple of things in general: I'm confident that among majority of Clan civilians many different languages are spoken and different religions are practiced in the privacy of their homes and off duty. SLDF English is lingua franca among all Clans and is spoken by everyone but it's often just one of two or more languages that average civilian would speak.
We know of at least one case when Clan leadership straight up implemented official freedom of religion in their realm (Escorpion Imperio) and I don't think they came up with it out of the blue so it was most likely something that existed already back in the Homeworlds in most places among civilians. Cloud Cobras were just the ones who put most work into religious matters and did it officially.
These are great points about
Dagda and a great write up on
Roche.
I want to add on to some points about other languages and religion.
In terms of religion, its very clear from source material that a number of clans were spiritual/religious from the very founding of the Clans: Nova Cat, Coyote, Goliath Scorpion, but
especially Cloud Cobra, with founding Khan Khatib referred to as the "Pope in Exile". So while Nicholas may have frowned and growled at religion, its very clear that it was accepted - even encouraged - by four entire
Clans - trueborn and freeborn alike.
Not sure how to fit that in to the traits that Alan is asking about, but I would think that any world that has a high presence of those clans is going to have the trait "spiritual" or "religious" or something.
I think the issue of languages spoken other than SLDF/Clan English is complicated.
Operation KLONDIKE is explicit that use of any language other than English - except for academic purposes - was severely punished ("New Order", p. 102).
But, that said, its hard to keep languages down. I would
imagine that there are still pockets of non-English speakers (esp. Japanese, Swedish, Hungarian, German), but that lacking formal education in these languages (because its illegal), they have morphed into creole or vernacular versions of their original language (modern examples of this are Texas German and Louisiana French). I guess we could call this "Clan German", "Clan Swedish", etc. And these languages would be difficult to understand by native speakers of the original language.
But given the illegality of speaking non-Clan English, is it right to suggest that there is a strong prevalence of secondary languages?
I think an exception to this is what Alan wrote about Homer. There are academic (religious) reasons for a freeborn/trueborn from Homer to know another language, but that language is going to be religious in nature and may not even be used for everyday communication. It is very different to know Hebrew, Arabic, Ancient Greek to read the Torah, Quran, Bible, but those texts aren't going to tell you words for "helicopter", "LZ", "orbit", "genetics", "chatterweb", etc.