Can anyone help me find this book composed of a fictional language?

A couple months ago, I found on Amazon a book written entirely in a fictional language. I remember in the description for the book it said something like „although you can‘t read the language, you will find recurring motives in the text“ or something. I wanted to buy it, but I do not remember the name of the book. Does anyone know the name?

Edit to make it clearer: it was definitely a novel, possibly fantasy, and the title was a singular word also in the fictional language (I think). The language used the Latin alphabet.

It was also a modern book. I looked at all the suggestions in the comments, but no luck so far.