"The Winds of Winter" was initially set to release before season 6 of "Game of Thrones" could premiere on HBO, but author George R.R. Martin has explained that this shall no longer come to pass. As fans wait for the book to launch, presumably before season 7, several new details have emerged, including the confirmation that the book will include Dothraki dialogues.

According to a report from the IB Times, linguist David J. Peterson confirmed his involvement in helping Martin write the Dothraki lines for "The Winds of Winter" in a recent Q&A on Reddit. It was further revealed that Peterson has aided Martin on the Dothraki language since 2013.

Peterson has been the primary linguist contributor for "Game of Thrones" and he is credited with being the expert that designed the Dothraki language used in the series, making it logical for Martin to approach him when writing Dothraki dialogues for the novel series.

However, it was revealed that no other languages will be explored further in the books. This means there will be no extensive exchange of lines in Valyrian or the dialect of those from Asshai. 

Fans speculate that the reason to explore the Dothraki language in the books is because of the way book five, "A Dance with Dragons," ended. In both the books and TV series, Daenerys Targaryen was captured by a roaming pack of Dothraki, known as a Khalasar, and it is expected that the only language that will be used within the group is Dothraki.

Peterson did jokingly state that Martin may be upset about Peterson revealing his contribution to the books and that the words he gave Martin may not be used at all as a means to spite him. 

There is no official word yet when the book is even going to come out, regardless of how much Dothraki and other material has been implemented into it, but widespread speculation is that it will come out at least prior to the premiere of "Game of Thrones" season 7.