I'm a bit conflicted on this issue myself. To give some context I was raised Roman Catholic and for a good majority of that time was involved in TLM parishes with the SSPX and Sedevacantist scene. I spent a good portion of my life praying and attending Mass in Latin, now I do have an interest in language (ancient or other wise) to begin with and for me it wasn't a big deal to "just learn Latin" so I could understand what was going on during the Mass.
Likewise there were plenty of people in the SSPX/Sede world who knew they couldn't ever go to a Novus Ordo church, but still had no idea what was going on Latin. This idea that there are only a handful of languages you can serve in was something that was condemned by the Western Church prior to the Schism.
During the time of Pope Nicholas I (the same one who caused the Photian schism) Sts. Cyril and Methodius were persecuted by German clerics who said the only three languages you could serve in were Latin, Greek and Aramaic. They outlawed usage of Slavonic in the Slavic lands and tried to throw Sts. Cyril and Methodius in prison.
Pope Adrian II and Pope John VIII both reversed the decision -- with the latter even condemning this idea you could only serve in three languages -- however after the schism the Papists claimed this decision either never happened or was invalid.
My Vladyka, Archbishop Andrei, only serves in Slavonic. When he joined the ROCOR in 1969, most of the Russians had the idea of "well unless you go to HTM, you're going to have to learn Russian". Only a few years later did Abp. Averky of blessed memory even allow English classes at Jordanville, so my Vladyka learned Russian.
There is also the fact almost all of his people are Russians -- and some don't know English very well -- so it makes sense he would only serve in Slavonic. I've seen and heard of some churches where they do things half in Greek/Slavonic and half in English, and while I'm not opposed to that it's a very imperfect solution.
Obviously with ethnic parishes, there's a lot that can be said (but what hasn't been said already?) about them being more interested in keeping their language or culture or whatnot. There are examples of ethnic parishes that have survived more than two-three generations -- such as St. Markella's in Astoria -- but I also posit something else: This sort of cultural paranoia about being afraid of losing language or culture can exist among American converts too.
I won't say where, but I personally witnessed three True Orthodox Churches all within about an hour of each other. One is Greek, one is American converts and one is Russians: the worst offender in not interacting with the others and being very "exclusive" in their mindset and attitude were the Americans. To them losing their "American identity" in the switch to Orthodoxy was too great of a risk and they were terrified of the Greeks or Russians coming and replacing their hamburgers and pizza with gyros and baklava or borscht and blini.
Obviously I can't give advice on your situation, I'm just sharing my thoughts, the Saints usually worked to translate materials into native languages and the practice of the Russian Church historically was to serve in the native language -- like what St. Innokenty of Alaska did with the Aleuts, Chukchi, Kets etc.
I also see the other side where in Russia today, the MP has almost completely abolished the usage of Slavonic and moved everything to modern Russian -- with the hope people will actually understand what is happening in the Liturgy -- but the people there are so secular and atheistic than even in modern Russian people can't understand the services.
It's a delicate balance and you'll never strike it perfectly for everyone.
