I noticed a trend in second language English speakers of using the expression "I see." as a response in conversations a lot. I think it's because in Japanese this is more or less a direct translation of なるほど which is common in casual conversation. But in English this sounds a lot more formal. In English, people almost never use the expression "I see" in everyday conversation. It's usually used dismissively or in a skeptical way when someone doesn't really believe or care about what someone is saying. It's actually not that common in casual English to really acknowledge what someone has said in this way. For example, in this conversation, Person A: What is your favourite food? Person B: I like ramen! Rather than responding with "I see." it's more natural to say something like "I like ramen too!" or "Oh really? I prefer sushi." Nobody would be upset if you said "I see" when English is your second language of course but I think it's a good example of how direct translations don't always function the same in another language. Also that formal language education often focuses too much on "textbook" expressions rather than a more natural way of speaking.