Considering there was virtually no dialogue in this book, I'm quite impressed by the author in writing a book, from the perspective of the "caveman" - who does not have the ability for speech, to make it as compelling and as interesting as it was. 
 What we know from the beginning: 
 The author includes an author's note regarding the Brocha's Area of the brain, which is responsible for speech/language production. It is left to the reader to make the assumption that without the Brocha's Area, one cannot speech or use language, however it does not speak to the intelligence of the individual. 
 We know that from the male narrator's thoughts, that he lives in a cave, hunts and gathers his food, and that his entire tribe was destroyed when a fire destroyed their home. When he (Ehd) meets Beh, we realize that he cannot communicate through speech. Therefore, we understand that he is a caveman that is lacking the Brocha's Area of his brain. 
 Our narrator comes upon a young woman who has fallen into a ditch that he created to catch animals for food and clothing. He has been alone for some time and is very happy that he has found a mate. Lacking that area of the brain, he cannot comprehend the noises she makes with her mouth, however he does have a "name-sound" of Ehd and determines that her name is Beh (short for Elizabeth, which he could not pronounce, and Beth which was also too difficult for him). So, it's one syllable words for Ehd. 
 What do we know about Beh?: 
 We know virtually nothing about her, except for the fact that she wears clothing that seems to be from at least the 20th Century (leggings with a round metal thing at the top, strange foot coverings that lace up, and a tunic that has no ties). Where is she from? When is she from? We do not know. 
 The entire story is told from Ehd's perspective while he tries to figure out why his mate is so strange, what with her weird mouth noises, and her disinterest in making a baby. And, the parts in which Ehd explains how he wants to "put a baby in her" got a bit annoying after a while. In fact there was one page that had him narrating that he wanted to "put a baby in her" probably 10 times... We get it, he wanted to have sex with her - but using that same terminology over and over again was killing me! 
 Again, I have to say that I was very impressed with the fact that this author could make such a compelling, and honestly a love story with almost no dialog and coming from the POV of someone who has no ability to speak - limiting the ability to communicate with his mate. 
 I do not want to go into anymore detail, except to say that the Epilogue is what made me rate this book 4 stars (rather than 3). The Epilogue was brilliant, and completely tied the story together. Kudos for that!