Long story short: I got a PhD a few years ago (let's say, in numerical methods for nonlinear PDEs). I've since gotten experience with a couple post-docs and a variety of collaborators, but I'm not really satisfied with what I'm doing. I feel out of place.
Earlier in life, I made a tough decision between science and humanities-- my other passion has always been, let's say, east Asian languages. If my bachelors program had had better language courses or options for "hybrid" fields like computational linguistics, I probably would have gone that route, instead of fully focusing on math.
I've sought out collaborations that might help me bridge the gap between math and languages; I've also looked at postdocs to help make the transition. I've reached out to leaders at research groups who do stuff I'm really interested in. The common denominator is: I'd need a PhD in some kind of linguistics to research seriously what I want. So...
What key things should I take into consideration when pursuing a doctorate, given that I have a doctorate in an unrelated field?
Please consider the question within the following context: I'm not asking whether having two PhDs is good or bad (I frankly don't care), how to needlessly pad my name with titles, or how to get two PhDs simultaneously. (That is all to say: this post doesn't answer my question.) I'm asking about what to expect when changing careers, specifically, if the source career is in one academic field and the target career is in another, unrelated field. Assume I've 100% decided to leave my current field and pursue this second doctorate, for the purpose of changing careers. Assume also that I already have substantial content knowledge in the target field, as I have a bachelors degree in it already, and it's been an avid hobby for most of my life.
Some sub-questions that don't need to be specifically answered, but I think help narrow the question: in what way could my current PhD be a hindrance in getting into a new program? Will my supervisors and colleagues see my past PhD as an asset, or as weird-looking mole they will try to politely ignore? What are other questions should I ask myself to prepare for such a non-traditional career path?
Note: I've edited this question multiple times in a vain attempt to get the duplicate label removed. If you agree, please vote.