Well I for one seems to have learned my languages as two independent things as compared to what you describe. When I'm writing here now I'm thinking in English

Well I for one seems to have learned my languages as two independent things as compared to what you describe. When I'm writing here now I'm thinking in English uninterrupted, not in Swedish (my native language), although I am capable of switching at will without trouble. Maybe it is because I was simultaneously exposed to both languages heavily when growing up but almost always from separate contexts (as in reading in English and listening to Swedish or vice versa, also including other media like TV and games, and music - our radio maybe plays 70% English / 30% Swedish). Since mixing up the languages would be noticed quickly, perhaps that's how I learned to keep them separately better than most? Far from everybody I know was as interested as I was in actually communicating in English. And I wasn't much around groups with individuals talking both languages informally in a way that could get them mixed up. It was typically one language or the other in any given context. When in English speaking crowds, I've been mistaken for American more than once. Don't know the nationality of all those people however, perhaps they too had English as their second language. But I've never had anybody point out flaws like those you mention in my speech. I would like to note that I do seem to have an intermittent "speaker mode" when I become a whole lot more fluent and eloquent, usually while I'm very focused and have something that I know I want said, and it happens in both languages (it's quite weird, both I and listeners notice the difference), and I think this state of mind is related to these concepts; https://en.wikipedia.org/wiki/Context-dependent_memory https://en.wikipedia.org/wiki/Context-dependent_memory https://en.wikipedia.org/wiki/Flow_(psychology) https://en.wikipedia.org/wiki/Flow_(psychology) > But once you go to writing an essay, giving a lecture or presentation, especially in one of the languages you don't usually do that in - you immediately realize how segmented your vocabulary is Annoyingly true - 99% of my tech vocabulary is English only, 99% of my day-to-day vocabulary is Swedish only (stuff like names of kitchen tools and such that don't come up if you don't live in a country speaking the language). I would like to note that when I said "casual" I meant "not formal", as in dealing with somebody in some authority or business people, not simply informal with the family. Haven't had acquaintances notice such things either. (And regarding formal conversations, I simply spend too much time thinking it through in advance for linguistic bleedthrough to become relevant.)