In Cultish, Amanda Montell discusses some of the most common language traits and behaviours present in some of society's most well known cults, and how some of those markers turn up in more benign, everyday settings. She shows us how despite how many of us wonder 'how could anyone possibly follow such deluded people?', these systems are built to draw in even the most rational of people. 
I found this book fascinating. I'd heard of many of the cultish groups Montell explicitly mentions before, but I didn't know much and thought the connections she drew between them were very interesting, and gave a lot of interesting insight into society and human psychology.
However, it was not as linguistically focused as I expected, and instead took more of a sociological perspective. Montell also came across as having a slightly 'better than' attitude, as she often implied that she would never personally be drawn into a cultish organisation herself (despite discussing frequently how factors such as desperation and optimism are a greater predictor for being influenced, rather than poor rationalisation skills).
Overall, I did enjoy this a lot, but it did have a couple of minor complaints.