I would recommend that you read it, and then begin to APPLY what you learn about her primary love language. It will inevitably lead to her saying something to you about you beginning to "speak" her LL, and when it does, you can share what you learned, and encourage her to read the book.
The book was eye-opening for me b/c I always thought that my wife didn't love me, based on how little she "spoke my LL." Through the book, I was able to see that she WAS speaking love to me, only thru HER love languages. It was (and still is) a challenge to be worked on, because we both need each other to speak our primary LLs more in order to be fulfilled in the marriage, but I no longer come at it from a position of "she doesn't love me," rather as a challenge to be worked on.
