Two languages to C1 concurrent or sequential?

[Ogrim]

If you are on a B1-B2 level in both languages, and you don't have a strong preference for advancing one of them quickly, my recommendation would be to work on the two in parallel. It is of course a question of personal preferences , but my experience is that dropping a B1/B2 language for a longer time can be pretty detrimental. I've had a couple of experiences like that with Russian, and especially the output part (speaking and writing) was very hard when I got back to it after a break of several months. I discovered I had forgotten a lot of basic vocabulary and verb conjugations due to lack of interaction with the language.

The idea of focusing on one language for three months and just do some "light" activities with the other, then switch, may work to some extent, but even doing some "light" activities may not be enough to maintain the level. I think you need to find a balance doing at least some "intensive" study activity in both languages even if you want to give priority to one of them. Just watching TV shows or reading Harry Potter won't do in my opinion.

[tastyonions]

Instead of going to the extreme of three months on, three months off, why not try alternating on a one or two-week cycle to start out? Very little risk of forgetting that way, and you still get the benefit of full concentration on one language at a time.

[smallwhite]

If you believe in the Forgetting Curve and the superpower of SRS, you'll know that you have to revise things that you've learnt, that new knowledge needs to be revised more often than old knowledge. We don't know how well you remember your stuff so we can't tell you whether 90 days is an appropriate interval or whether it is too long. It could be appropriate for the present tense conjugation that you learned 3 years ago. It could be too long for the relative pronouns you learned yesterday. You don't know what the ideal interval is either. But you already know that the breaks you've been taking are too long ("the first has now slid back to B1"). Take shorter breaks, then. Whether you switch languages once a week or once a quarter, you're studying each language for 180 days per year just the same.

Personally I don't feel much backsliding in my romance languages, whether I'm A-ish or C-ish and whether breaks are for months or for years.

[Ani]

Have you identified the biggest areas of need to get yourself to C1? Is it grammar, conjugation, vocabulary or just quantify of material needing to be consumed? The answer probably lies in more thorough analysis of the problem.

IronMike has posted some good descriptions of the two week study rotation. I might be tempted to study intensively in one language for a time block, extensively in the other and then swap. The extensive block would not be lazy but rather aiming to complete a super challenge worth of native materials in some amount of time. Maybe one per language per year.

[tarvos]

My frustration is I feel if I had concentrated on a single language to C1 or C2 level, then there wouldn't be so much backsliding when I switched to learning the other. At the moment I seem to go to B2 then switch to the other language, it gets to B2 but the first has now slid back to B1, so I bring it back, but the other has slipped. Hence I seem to be eternally B1 or B2 but not progressing.

Doing both can cause a lot of code switching and problems for me personally.

Anyone dropped a B2 language for six months or a year? Difficult to return?

Also anyone stooped using a C1 or C2 language if so how hard to pickup where you left off?

A language at B2 can't drop that fast. Here's the thing. If you're at B2, that means you should always, whatever happens, be able to drop the language for 3 months and be able to pick it up with very few hints of rust. B2 means you are entirely comfortably socially, you can discuss topics of your interest at length. I have never, ever, ever dropped a B2 language for a while and ever failed to communicate in it later on. All my B2 languages are languages I am comfortable in, even the weaker ones such as Italian or Portuguese. I can drop these for months at a time and go back to using and reading them whenever I need them, even though everyone will notice my Italian or Portuguese are rusty.

Probably you're B1 at all of them and you improved a little bit, but not enough. The thing about B2 is that it is a level where your social ability is such that you don't get lost when you go out for a night on the town and have some drinks, for example. I spoke Italian for almost a whole day in Vienna, and I certainly failed marvelously at times, but I speak enough Italian that it doesn't matter. I could do the same in Czech nowadays. (Not if going out with Slovaks, though).

The truth is, if you can't drop languages, you are not B2. That's my experience, full stop.

The answer to your question therefore is - get one of the two languages to a level where you can comfortably drop it for a while without worrying about it. If you slip a tiny bit or forget a word or two every once in a while - fine. Happens to me in languages I'm excellent at. Happened to me today in Russian and nobody doubts my skill in that language.

The best way, in my opinion, is always one by one. The reason I am only dabbling or doing maintenance/improvement right now is because I have an arsenal of languages at my disposal and they take a lot of time to maintain them, especially since I have to juggle a pretty silly arsenal of languages as it is and my levels fluctuate a bit anyway. I will do projects in the future, of course, no doubt, but right now I have no desire to because my existing arsenal needs some polish and sheen.

That's not to say I won't dabble in Shanghainese some more or learn a bit of languages x, y, and z on the side. But if I have to juggle, say, Korean or Hebrew next to what I already have, the effort becomes too big. So I need to do it when there's a reason to do so, or when I decide that for my life, learning Korean is vital and I suddenly realize that my passion for it has grown. And there's nothing wrong with that.

[lingua]

If it were me and they were at roughly the same B2ish level I would continue to C1 concurrently alternating days. I have nothing to base that on other than gut feeling. I think doing them sequentially risks losing too much of the one done first. I have never studied French but Italian is my strongest non-native language and I know that when I spent less time with it a few years ago I lost some vocabulary. For me, using the language several times a week is what keeps me steady or progressing.

[trui]

I second the recommendation to focus on getting one of your languages to B2, although there's no reason why you can't dabble in the other at the same time. Once you're B2, the language will feel even more like it's yours. It'll feel kind of like your native language, except you'll be very aware of your limitations and that awareness will drive you to learn even more. But you won't need to do any more formal study (although you can if you want). You can just enjoy your newly aquired second language and read books, watch tv, chat with friends and so on. Once you're at that point you can put more focus on the other language and get that to B2 as well.

[rdearman]

The truth is, if you can't drop languages, you are not B2. That's my experience, full stop.

You're probably correct. I have been ignoring Italian then spent a month listening to Italian TV and haven't had a problem in Sardinia this week, someone mistook me for a native which was nice (didn't last long before I got caught out) and my wife said she finally has more confidence in my Italian the the waitresses English. I could drop Italian for a awhile. I say it goes back to B1 but that is probably a lack of self confidence.

But I gathered from your post that you recommend concentrating on a single language until C1 then switching to bring the other up to C1 as well?

Flipping between or doing both isn't recommend?

[tarvos]

The truth is, if you can't drop languages, you are not B2. That's my experience, full stop.

You're probably correct. I have been ignoring Italian then spent a month listening to Italian TV and haven't had a problem in Sardinia this week, someone mistook me for a native which was nice (didn't last long before I got caught out) and my wife said she finally has more confidence in my Italian the the waitresses English. I could drop Italian for a awhile. I say it goes back to B1 but that is probably a lack of self confidence.

But I gathered from your post that you recommend concentrating on a single language until C1 then switching to bring the other up to C1 as well?

Flipping between or doing both isn't recommend?

I recommend B2 for one, B2 for the second, then C1 for the first, C1 for the second.

B2 is the barrier level you need. Above that, you can do both or flip-flop as much as you want. Beneath that, you need focus.

Let's say I'm going to study Korean (I have an A1 level - false beginner). If I wanted to maintain Korean, I'd need to get to B2 (however long that would take - I'm suspecting a year minimum with no other distractions and including travel to the country). I also want to study Icelandic (about A2). I'm suspecting more like six months here. (Closer to good languages). If I start flip-flopping them, I lose both my Icelandic and Korean, because I never get to B2.

But if I improve my Icelandic enough in six months, I can leave it be while I study Korean (I may do a little bit of Icelandic on the side, but it should take no more than 20% total of my study time max, less if I'm sharing with others). That way I can get them both to B2 and there's no issue. (Some other really neglected B2 languages may drop back to B1, but a short refresher will get them up and running in no time again. And they have to be neglected over a period of years, not a few months).

[zenmonkey]

You know, go comfortably into the the dark forest, the house is just around the corner and you can always back out. Hit one language hard for a week, then two, then three - do you suddenly feel that this is getting results? Do you still feel you haven't wandered away too far from the other language?

Build in those points of self-reflection into your calendar so that your mind can put the worry and reticence away knowing you'll do the check and can focus on moving forward. If six weeks in you need to take a break for whatever reason at least you'll know the answer for yourself.

(my vote is do not try to learn two languages of high lexical similarity at the same time)
(that way lies madness, let me shun that)