I once knew a guy on a different language exchange app. He'd been learning Russian for seven years or so, and his skill was incredibly impressive (to me). One interesting thing was his "requirement," written in his profile, that he would only communicate in Russian with other people, and never in English. Some people criticized him, saying it was hardly fair for him to demand people help him without anything in return. He said it was just "his rule."
Without trying to reduce everything to the level of economics, there is a certain bartering that goes on when we do language exchanges. In theory, we sacrifice half of our (potential) learning time to helping others with our language. If we have to choose between no practice at all, and doing language exchanges, giving up some of our time is obviously the better choice. But if we start thinking long-term, half of our learning time, when it comes to learning languages, could be another year, or two, or three.
My best language partner, with whom I've been communicating for about a year, speaks with me about 95% in Russian, and 5% in English. My partner doesn't even especially want to learn English, hence the discrepancy. Without that practice, I would not be even close to where I am today.
What are your thoughts? Is it reasonable to seek out such agreements between people? Is it unfair? What are your experiences with this and what is your wisdom?
