I wholeheartedly agree. While I admire OP in his charitable endeavors. I can't help but think that this puts the incentives on studying things that offer little to no market value. Market value of a degree tends to be a huge predictor of how needed that skill is in the market. I don't know if what Tanzania needs right now is language PhD's instead of Architects, Engineers, Doctors, etc...

An important point is that this is not for us to decide. Development doesn't happen by us telling others how to develop, but by giving them the means to develop on their own. Maybe this person finds out that her choice was a mistake, but realistically, I believe that language studies is not the worst choice. There are many languages spoken in Tanzania (and any other african country) some of which are at risk of slowly dying out. Having a background in languages could make the difference in her ability to support her local language, not only to preserve it but to strengthen the confidence and self-image of its speakers which in itself can make a great impact in the development of that region. It could even be that it affects how much parents value their children going to school. We don't know any of this. Only the people living there can figure this out. All we can do is to provide some resources to help them along.

IMO this kind of hyperoptimization will cause more trouble than good. It's cheap and productive just to get humans to advance through any sort of education. This person will almost certainly contribute more than she would have with a 5th grade education.

Let people self-direct, even if not everyone follows an optimal route. It's a numbers game.

One thing they probably don’t need are bad unhappy professionals uninterested in their field. The people from the village know better than us random internet commenters what their heart is in, and they have just as much right as us to pursue their dreams and interests.

The focus on “the market” is a disease which narrows our thinking. For all we know, her language studies might allow her to communicate with many more people and cultures from the outside and bring much more prosperity to the village than an architect.