Evgenia Kashaeva claims she reached the following level after her one-year program:
- German: B2
- Spanish: A1
- French: A2
- Chinese: B2
- Czech: A2
Czech was the only new language; she had been learning German and Chinese for an unspecified length of time (presumably at least a few years) and had learnt some Spanish and French and then neglected it. It is not clear how she determined the level she reached after that year of intensive language learning; since she does not mention any official tests or certificates, these can only be rough estimates - possibly overestimated.
According to my own research, native speakers of a Germanic or Romance language would need the following amount of classroom hours to reach B2 (or in some cases B1):
- French B2: 720 hours (or 80 minutes per day for 18 months, or 2 - 2.5 hours per day for a full year) (assuming it takes as long as Spanish),
- English B2: 720 hours (see also Spanish, as above),
- Standard Chinese B1 (!): 960 hours (or 105 minutes per day for 18 months, or roughly 3 hours per day for a full year),
- Japanese B1: 960 hours (the same as for Standard Chinese),
- Korean B1: 960 hours (the same as for Standard Chinese, though it may go a bit faster due to the easier writing system).
Reaching this goal within a single would require 13-14 hours of language instruction per day, plus some hours to review what you've learnt. (When I was learning Chinese, I spent as much time with it at home as in the classroom, though this was more than the average course participant.) When you add the time you need to review lessons, vocabulary etc at home, you reach roughly 20 hours of language study per day. In my opinion, this is not humanly possible, even for a very young brain. [Edit: When this question was originally posted, it was not clear that "one year middle" meant a year and a half.]
If you want to reach this goal in 18 months, you need roughly 8 hours of language instruction per day, complemented with a few hours of review and self-learning. This is simply too much to be realistic.
The tips from Evgenia Kashaeva's are worth following:
- Don't study in blocks of two or three fours but use the Pomodoro technique and take regular breaks. (Kashaeva doesn't mention the breaks explicitly; the "90 minutes at lunch" are strictly speaking too long as a single block.)
- Focusing on one language per day will probably reduce the risk of interference and confusion between the different foreign languages. On the other hand, the six days that pass before you return to the same language will cause you to forget a lot. (See the forgetting curve. You can reduce this a bit by adding a 20-30 minute session in which you quickly review what you learnt the day before. (For example, in the proposed schedule, review some Japanese on Tuesday, some Korean on Wednesday, etcetera. Make sure you take a good break before you tackle the "main" language of the day.)
- Make a plan for 12 weeks instead of 12 months. See also Donovan Nagel's advice on setting both "macro goals" and "micro goals".
- It is a good idea to combine self-learning with Skype sessions. Note that these are usually not free unless you engage in an (online) language exchange in which you help your exchange partner learn your language and they help you learn their language. Of course, helping your exchange partner will block time in your language learning schedule.
Note that Evgenia Kashaeva did not set herself the goal of reaching B2 in German, A1 in Spanish, etc. These are just the estimated levels she happened to reach after those intensive 12 months. What I recommend is setting "practical" goals, i.e. things you want to be able to do instead of a level you want to reach. Defining goals that correspond to levels does not fit very well with the technique of making a plan for 12 weeks, since reaching the next level usually takes longer than 12 weeks. If you notice after 12 weeks that you have not reached the level you had defined, you might get frustrated. However, if you define a dozen smaller (and realistic) goals, you will reach at least several of them and you will have something to be satisfied about.
So you can go ahead and make a plan for the next six weeks. Find a tutor or language exchange partner for each of the language you chose. And if you need to find appropriate learning resources, you can post new questions about that on this site.