[bivargen]

While I do not doubt that your spouse, this is besides the point, the point is that Min Nan pronounces the first phoneme of the word for “tea” with a dental stop, other chinese variants/languages realize the same phoneme with a dental affricate.

I do not know if the article author/cartographer ever studied linguistics or phonetics, but this is the main takeaway from the map for me, a linguist, the pattern is the message, not the somewhat imprecise data points.