I think in retrospect I should have been a bit more relaxed about language acquisition, but I am a translator, so really expected myself to be able to teach my kids to be perfectly fluent in both languages. Translators view fluency very differently than the average person - professional hazard. Due to the circumstances described above, that wasn't a realistic goal, and I needed to adjust my thinking and put less pressure on my kids and myself. There is also a trend in our community toward judging people based on our kids' language competence, which is wrong, but there you have it. Being active in the community made me feel that pressure as well, although I have tried to work on having more events and activities that all language levels can participate in.
I agree that we should be happy about those perks of bilingualism whatever level our kids end up achieving!
ITA with the point that different children just respond differently. My son is not very verbally advanced at all. I mean, he's not behind, he has a large vocabulary, but he is much more of a physical guy. He was way late on his language milestones (even needed speech therapy) but way, way early on physical things. Even now - even though he talks nonstop all day long, he is much more of a physical thinker than verbal or even artistic. He can take things apart and put them together, he can figure out complicated gears, etc. He did not and does not pick up at all on Hungarian. Maybe a few words here and there, but he just gets frustrated when asked to even repeat simple words or try to listen. He could if he wanted to I think, he has a steel trap of a memory (he's 5 now and can easily remember back to when he was 2) but he just doesn't use it for words.
My daughter on the other hand is average on physical milestones, very much ahead on drawing and puzzles, way behind on letter recognition (she's almost 5 and can't even come close to writing letters or even her name)... but she is much better with picking up language acquisition, can mimic the words flawlessly, has a pretty good vocabulary for not being used to it all the time... And she hears the nuances of the letters, picks up when others aren't using it right. My son on the other hand doesn't even hear half the more unusual sounds, can't distinguish them, can't pronounce them.
Same family, almost same age (10 months apart), same environment... totally different kids.
That's the whole point, and I think it answers OP's question. This is the extent of "control" we can have over our children's language, and it can go a long way imo. And in my experience, as long as you you can keep the language until you go past the toddler and preschool years, you can explain the importance of the minority language to your dk and they may choose to use it on their own. Now my ds wants to learn to read and write in Romanian and refuses to answer me in English (even when I talk to him in English when he has friends over).
We are all born with the capacity of learning language; the proof is that we all learn at least one. Agree, some people are more proficient with words, even in our mother tongue. But language is just a tool for communication, if we don't have to use it, we will forget it. My father had to learn German at 50, when he went to work in another country. I've seen so many examples of families who maintain their minority language, and some who don't. The key is, does the child need to speak it, or he doesn't.
My three kids learned at totally different paces. My oldest didn't talk till 2 1/2 then mixed endlessly. My two girls never tried to speak to me in French. One was very advanced and one, more like her brother but not as behind. She made all sorts of pronunciation errors in both languages.
But none of these held them back from speaking both languages. They just learned them at different paces.
I don't switch to French ever. The kids at school are very cool about it. They were blase about it until they found out they'd actually have to take it as a language in middle school. Then we had an audience lol! But that was a separate issue. We never hold conversations in front of non-English speakers or I "cue in" ("he hates it when..." kind of comments, less patronizing than translating). It's like X's Mommy speaks Y to her kids, and she also has blond hair. It just is and they're fine with it.
Now they notice that the middle one is more advanced. Yes, she is. You sing better. You build stuff better. Everyone is not equal. Get over it and move on. But I would never compromise their language skills based on their abilities and hope no one reading does. Even a slower learner needs to keep up at family events, interact in the same way with the same parent, etc. So what if there are more mistakes? A slight accent? I wouldn't speak less English to any of them, just because they weren't picking it up fast enough. I know two children who are bi (one's tri) lingual here with Downs. Didn't keep them from learning! Sure, I bet they have less vocabulary and make more mistakes but they speak both (all three) languages fluently.
I wanted to post a link to a US site called Mantra Lingua that has books and materials in some really rare minority languages: https://www.mantralingua.com/usa/home.php
I have a few of their books in Russian and they're quite good quality.
Tynka - I have also noticed that the quality of the translations in Latvian kids' books is sometimes pretty bad.
That's what I do a lot.
You need to put yourself on a three-week Lithuanian "diet". This is simply habit. I know. My dh can't speak English and I live in a part of France where English is rarely heard. I was living and working in France before and I had to really think about it. But once the habit is set, there's no looking back.
Give yourself the goal of three weeks so that you're not beating yourself up or feel pressurized.
Vocabulary building is your long-term challenge. It doesn't stop. Not a day goes by when at least one child does't know a word. They usually ask for it in English. My YDD once said "I need a pen, not blue but the darker color". There was a fish net next to the fish bowl and she asked what it was yesterday. The only difference over the years is that the vocabulary becomes more remote and specialized.
Try to insert vocabulary "lessons" in your normal lives. Instead of just handing him a drink, say "Orange juice" in Lithuanian to him as you pass it to him. I didn't do this with my son and didn't make the same mistake with my two dd's. Just keep "feeding" him vocabulary. Grammar is a different story. I just got a paper marked "List Birthday" on it. She isn't aware that it's wrong but when she doesn't have a word she needs, she IS aware of it. Lacking vocabulary equals lacking confidence. A child who is missing words can't express themselves.
Instead of asking him what he's doing, ask him "Are you playing with your...?" Point out objects as you drive around or when you're just hanging out. He'll remember "dog" when he hears the dog bark, for example.
It will also help you crack the English habit.
How old is your baby?
It's great that you communicate in "whatever feels right" but you might find that means that Greek is not getting a lot of exposure.
It can be hard to be the only one speaking the language with a child. I'm my children's only consistent source of English. I spoke French and lived in France before meeting my French hubby. Sometimes I have to force myself to speak English, especially in the beginning. It's not just what I feel like speaking. I had to set in place the habit.
The approach a parent speaks exclusively one language works best if you have great everyday exposure to this language
That's true but not an absolute. Not all of us can get "everyday" exposure. Remember that many children, including mine in German, are fluent even if they don't use it everyday. My kids only had German twice a week in elementary school, but it was full immersion, all day. It still worked, albeit slower.
Every word of English you use with your child is one less word of Greek she's getting.
I have an almost 5 year old and an almost 2 year old. I'm their only exposure to Icelandi language (spoken by ~300.000) as we live in Finland. In a way it is easy for me, Finnish is hard to speak so trying to speak that to them would feel unnatural. I managed to get the older one to speak to me only in Icelandic, she struggles but manages fairly well. It took a lot of work when she was younger.
Like I said I only ever speak to them in Icelandic and wont speak in other languages to them to be polite to those around me. Politeness is nice but I am their only exposure to an entire language so me muddling with other languages weakens the minority language's position, or so I feel.
Tynka - No advice, just sympathy. Do the best you can. I know several Latvians who have learned the language as teens/adults because they developed an interest. I completely understand how intimately linked our languages are with our culture and identity. It's hard, no doubt about it. Just keep plugging away. You'll be surprised what gets into their little heads! And someday, when your son wants/needs it, it will come back out. Don't lose hope!