These aren't things I regret, but they are things I would do differently with the benefit of hindsight. I don't think what I did were mistakes, but now I see things could have been done differently.
1. I wouldn't have come to the field intending to do a PhD.
While I'm exceptional, there are limits to my greatness. The ability to obtain physical books and the necessity of time to focus has meant an inability to progress in my dissertation as I would have liked. This was okay at first but the problem has grown.
It's always a little dangerous to extrapolate from one's experience to a general rule, but I would generalise anyway and say that the exceptional cases are indeed that, exceptional. Missionaries should not try and write doctoral thesis in the field, unless perhaps their topic is on the field itself.
2. I should have studied Mongolian more aggressively.
Related to 1, our full-time language load in our first year was me studying 3-4 hours a day, 5 days a week. This was quite exhausting. But it also meant I went home and then worked on a PhD. If I wasn't doing that, I think it would have been better to pour 7-8 hours into language a day. I would organise it differently though. I had great teachers, and would keep those 3-4 hours individual lessons. For the other 4 hours a day I would have employed some private tutors and directed the learning myself through something like WAYK or another field-methodology for acquiring language. After six months of this, I would have started doing field trips. They aren't really in my nature, but I think they would have served me better.
I think this would have brought me to fluency faster and deeper.
3. I would have invested less in fellow foreigners.
Again, I think we made the right choices with our situation, and I don't think this is universalisable. Especially I believed we played important and key roles in serving the English language church here. Indeed, through a transitional period our presence was perhaps vital.
However, English language-people investment always came at a cost of Mongolian people investment. And Mongolians are very (a) collectivist in their mindset, (b) tend to value spending a lot of time together. I think to have integrated better, earlier, and deeper, we should have just realised how necessary it was to commit one-way on this front.
Instead our time has been divided, and so I have often felt tired from trying to serve in two different contexts, without ever developing truly deep relations on either front.