Wanting to go to church in one's native tongue is not 'ethnic pride'.
Church Slavonic was never anyone's "native tongue." It is a liturgical language based on Old Slavonic dialect. I personally prefer Church Slavonic, but outside of the Russian Church even the Serbs have recently started to use modern Serbian vernacular (except for prayers) which sounds odd and clumsy compared to the seamlessness and incredible phonics of the Church Slavonic.
Slavonic is the language of Slavic Churches, and it is not even limited to Orthodoxy. Carpatho-Russian Uniate Catholics still use it, and Croatian Catholic parishes used Slavonic for centuries over Latin.
Slavonic does not define any particular Slavic ethnicity -- no Slavic tribe can claim it as exclusively belonging to it.
It is as much Serbian, Bulgarian as it is Russian. It's our common language and it makes your liturgy intelligible to me as much as my liturgy to you.
It's a preference of eastern Orthodox Slavs, especially for people who don't speak any other language as well as their own, and most immigrant communities are that way.
But, you must remember that going to church is not about "enjoying" the show, but about receiving the Mysteries. A church should be an environment where prayer is made possible, and distractions are minimized. If you have tor struggle with the words and if, as often happens, there are screaming babies that everyone pretends are not there, or bickering siblings in the church, and their parents have no intention of taking them out, the point is lost -- your mind wonders off, and worse you might even become angry, even if for a second or two, and then it's a struggle between thinking of God and trying to ignore the distractions or keeping up with the liturgy one does not understand.
The whole point is this when it comes to language: it's a barrier. It separates people. It is contrary to the idea of Christianity, which is to emulate on earth the loving communion that is the Trinune God. That's why I thought the idea of Latin was good. No one speaks Latin as a native language, so it's foreign to all. It made possible for any Catholic to go anywhere in the world and hear one and the same liturgy in the same language that all had to learn, but that bound them into one community.
But, people refused even Latin for selfish reasons and for reasons of laziness and commodity. They wanted it in their own native tongue and damn the rest! Very charitable and very Christian indeed (not)!
In Chicago, where there are many Serbs of all generations, the liturgies are given in Slavonic/Serbian and in English to accommodate those Serbs whose language precludes them from getting the full effect of the Divine Liturgy. Even though they are all Serbs, that in itself divides one and the same ethnic community and separates them.