Marie Brennan’s Turning Darkness into Light is not a Lady Trent book. Technically.
It is, however, a sequel to the Lady Trent books, featuring Lady Trent’s grand-daughter as the protagonist; and while the younger protagonist isn’t a naturalist like Lady Trent, she is a linguist who gets pulled into deciphering an ancient Draconean tablet; and while the book isn’t told as a memoir, it is told almost entirely through diary entries and letters, so retains a lot of that feel.
So yeah, it’s basically a Lady Trent book. And as one, it’s an enjoyable read. It’s focused around both a literary-historical mystery as the heroine attempts to decipher ancient tablets, and a political mystery as dubious characters appear and violent happenings occur.
It’s not super-deep or anything, but it mixes up the formula just enough to keep things interesting. Recommended for anyone who liked the Lady Trent series.