1. There may be a need evidenced to know a bit more about both Romany and travelling or tinker cultures to minimise the risk of being offensive.2. Why "who speak English" but "that speak American". I tend to use "that" as synonymous with "which" but I notice the micorsoft grammaar checker seems to disagree. Is this another manifestation of the difference between the two languages?
3. The science of information retrieval has taken a beating since computing power has grown so much but for an understanding of the fundamentals of irrelevancy and "false drops" it may still be worthwhile to start reading with "Information retrieval theory" by Kent, although it is almost 30 years old, if you can still find a copy