It is very obvious that this book was written over half a century ago (it contains many outdated and, in other times, offensive words that academics and the general public would not use to describe people). This book would only be helpful in the sense that it provides insight into how philosophers and those psycholinguists thought at the time. The current academic literature has moved on from the discussions found in this book.
The best reader on sociolinguistics & linguistic anthropology ever. Even on pragmatics with John Searle's 'What is a speech act'. Strongly recommended to my students.