Fully half the Latin books I see in the shops are these silly things with lists of modern expressions allegedly in Latin. It seems to me they are not taking the Latin language seriously; it is presented as an amusing code in which to write English, rather than the actual language of a civilisation. It reminds me of the sort of scenes you find in American teen movies, where a grandma or school principal will turn on some rap and start dancing. You're supposed to laugh at the clash between old and cool. I've always just found it lame. Do we need specifically colloquial expressions in order to speak a language? I don't think so. There is no need for language to be divided into these registers. Remember that all formal language was once colloquial. The language used by the esteemed Classical writers would have been considered quite slangy by speakers of Early Latin. “Where are the subjunctives such as “faxim”?”, they might ask. “How uncouth to put V instead of O in all these second-declension nouns!”, they might exclaim. In any case, we're not really talking about colloquial versus formal, but attested versus invented. In particular, there are many situations in which you or I might utter a certain English phrase, and yet the Romans might not have said anything — and vice versa. I am reminded of an occasion when an Italian acquaintance of mine asked me how to say “buon appetito”. I told him, “we don't”. As I continued to explain how, where I'm from, we don't feel the need to say anything to people just because they are eating, he got more and more annoyed. He just wanted me to say something like “good appetite”, but I refused. The fact is, we just don't habitually say anything of the sort. We're aware that people do so in other countries, and that's why we're familiar with the French term “bon appétit”, but only pretentious people would actually use it themselves. You might occasionally get “enjoy your meal” in a restaurant (especially if the waiter has watched too much American TV), and really religious people might say grace. But the norm is not to say anything, in the same way that we don't feel the need to say “have a good pee” to people heading for the toilet. He didn't get this. He felt that his Italian customs were universal, and that every language had to have an exact equivalent for them. The fact is that English is a language perfectly adequate for all everyday conversations, despite the fact that we don't have an exclamation to utter if we see, for example, someone eating a handful of peanuts. Therefore, it seems that Latin is quite adequate in that it has “salué” as a greeting. There is no need to force individual translations of “good morning”, “good afternoon”, etc. Is anything actually communicated with such things that you cannot communicate with the actual, attested greeting? And why must English be the king of languages and define what modernity is? Why not force Latin into the Spanish mould instead, where “buenos días” serves during the morning and early afternoon, and “buenas tardes” is for the late afternoon and the evening? I say to use made-up Latin only when strictly necessary. P.S. Sorry to be a nerd, but I use grammar-observing book-English when I speak too.