In today's apparently civilised society it is no longer acceptable to pepper conversations with casual racism. Where that reflex exists, it must be contained, or at the very least buried within rhetoric about immigration and terrorism.
But there is a glaring exception - one ethnic minority that remains fair game.
"Gyppo". "Pikey". They're not pleasant words, but they'll hardly have you run out of polite society. They don't elicit the same outrage that other racial slurs do. In all likelihood, many people use them without even realising that they are racial slurs.
Most pupils leave school knowing about the genocide of the Jews in the Second World War. But what do they know of the equally brutal treatment of the Roma? They too were deemed "lives unworthy of life" according to warped Nazi ideology. They too were targeted for extermination. They too suffered huge casualties - perhaps half their entire population in Europe.
In Bury Me Standing, Isabel Fonseca's magnificent study of the Roma, she refers to their singling out by the Nazis as "just another episode in a more or less continuous narrative of persecution". After centuries of mistreatment, many Roma are deeply suspicious of others - and that allows prejudice to breed.
Roma typically prefer each other's company to venturing into what they perceive as a dangerous outside world, limiting the interactions with others that are the most powerful antidote to sweeping racial generalisations.
It will come as a surprise to most Scots that up to 4,000 Roma people may be living in one part of Glasgow (see pages 18-20). There, too, they rarely leave their tightly knit communities.
And, as elsewhere, the Roma's levels of education are abject. Their children typically appear sporadically at school and do far worse than other Glasgow pupils. The reasons are complex, but a historical fear of authority and the differing aspirations within their patriarchal and self-contained communities offer partial explanations.
But something is happening in Glasgow. School is providing a gateway to services, cinemas and swimming pools. Girls are seeing futures for themselves that their mothers never did. Families are starting to view Scotland as a home, not as a staging post.
Problems remain, but schools in Glasgow - notably the remarkable Annette Street Primary, where nearly three-quarters of pupils are Roma - and associated services may be achieving something of considerable note.
In some countries Roma people are accustomed to having their children streamed, usually unnecessarily, into special schools. They are used to being treated as deficient, even by those whose intentions are benign.
The day-to-day work of gaining trust, of showing these families that school can help, is painstaking but the unifying principle in Glasgow is simple. Here, Roma families experience something that their forebears may never have known: acceptance.