What's so good about it? the curious nature of ‘good-’ greetings

Summary

The English way of placing the word ‘good’ in front of the time of day as a greeting feels natural and sensible to English-speaking people, and a quick ‘good morning’ or ‘good afternoon’ comes out of one's mouth without a second thought. (And Australia's ubiquitous ‘g'day’ comes out of the mouth not only without a second thought, but without a second syllable!)

It may seem a highly trivial form of greeting – until you start looking closer.

Saying ‘good + time of day’ is a common greeting among Indo-European languages. The Germans say guten Tag, the French say bonjour, the Italians say buon giorno, the Spaniards buenos días, the Macedonians dobar den (in most Slavonic languages, dobro means ‘good’), the Poles dzień dobry, and so on.

But other cultures and languages don't use this form of greeting at all. The Chinese, for example, commonly say ‘Have you eaten?’ as a greeting. The normal Arab greeting is ‘Peace be upon you’. The Masai ask ‘How are the children?’, and the New Zealand Maori encourage you to ‘Be well’.

MYSTERIOUS RULES

Although ‘good-’ greetings seem simple and straightforward, there are several rules governing their use that sit in the backbone of English speakers, yet defy explanation. Some rules are:

You can only greet once. For example, you can say ‘good morning’ to your neighbour every day if you like – but never twice in the same morning. If you meet again an hour later and say ‘good morning’ again, you may be seen as a bit strange.