For someone interested in the live, change and "flow" of a language an entertaining book. Without doubt the young author did some research. Finally obviously the storyteller took charge of several chapters (si no è vero, è trovato bene). The German influx into American English is not really precise. Just think about the thousands of German soldiers fighting for the British Crown in the war of independence, most of them staying in New England. As well as the wave of German migration to the northern US at the end of the 19th century. Both have been neglected. A short trip to Nebraska, e.g., will tell you many stories about language ("a sack of groceries" might be handed over to you). Many Asian rooted word's explanation is interesting. But I would not count it as first row experience. So take it with some skepsis.
If you like easy digestable popular science with interesting facettes it is recommendable. If you attended some related University classes, it sounds more like a story book, than the real thing.