Thanks

Uly, it's been a while since I tortured you with my questions...))

In this case, can we say:
I started asking how it was that (s)he happened to know the language so well?
If the above sentence is correct, does anything change in meaning compared with your version?

Hi, Russ — never a torture, always a privilege 😉
Yes, there’s a very significant difference. STARTED TO expresses that you momentarily thought about doing something, but then decided against it: “I woke up last night to someone opening and closing the front door at 3am. I walked out of my room, looked downstairs and saw a shadow moving through my living room. I started to call the police, but then saw the figure walk into the kitchen and realized it was my roommate sleepwalking again.”

or… “Last night, my phone rang at 3am. I started to answer it, but then thought it might be my stalker, so I just silenced it.”

Based on that, I may have misunderstood the original Russian here because there’s no context. Correct me if I’m wrong.

Thanks.
As for your question about the original version - in Russian it can be both. The original doesn't tell us if the person stopped asking about the language or actually continued with the question. Here are 2 examples:
я начала спрашивать откуда такое знание языка, но тут же перестала, когда увидела, как на меня смотрит его жена ))
OR
я начала спрашивать откуда такое знание языка, и он рассказал, что он раньше жил в англоязычной стране.

Both examples above sound good in Russian meaning that if we say "я начала спрашивать..." it doesn't necessarily mean the person stopped asking the question. So, your translation is perfect.
Now back to my question. So, in English whenever we use "started to..." that means the action we started to do will be interrupted/stopped?

In most cases, yes, because when it refers to the beginning of an ongoing action, we normally use the progressive. But then it depends on context. A lot of Russians write essays that start with “I started to learn English…” 😂 It sounds like they started, realized it was hard and quit… but that’s not what they mean.

My translation here on this post can only mean that they intended to ask, but then thought better of it. The reason is that this post suggests one simple, momentary action.

Ok, let me make sure I understand.
Let's say you gave me a book to read. While reading I didn't like it and I stopped. In this case, I will tell you:
Last night I finally started to read the book you gave me but stopped b/c I didn't like it. (is this correct?)
BUT
If I like the book and want to continue the ongoing action I should probably say:
Last night I finally started reading the book you gave me and so far I like it.

Are both snippets above correct?

Last night you STARTED READING the book, but stopped a few pages in. If you STARTED TO read it and then changed your mind, you didn’t read one word… maybe didn’t even crack it open.

“Last night I finally started reading the book you gave me and so far I like it” is very good. And even better: …so far, I’m liking it. (Russian textbooks/teacher/know-it-alls will tell you not to use the progressive of “like,” but in the real world, we use it to express our impressions even while we’re still experiencing something.)

I have the Telegram app installed on my phone. Sure, I'd love to join. Let me know the details.

I tried to search for Uly Marrero on the Telegram app and there was nothing. Did you set up your user name? If so, what is it?