While the English language settled on "hello" as its customary greeting, other languages forged their own. Some were influenced by English, others developed independently – yet each carries a distinct cultural flavour, hinting at the social norms and stereotypes we have of the people who use it.

In Germanic and Scandinavian languages, for example, "hallo" and "hallå" are phonetically harder and feel more efficient and no-nonsense than the lyrical, almost poetic quality of "hola" and "olá", favoured by the Romance languages that are associated with more effusive stereotypes. Elsewhere, some greetings carry traces of national history: from the Dutch-derived "hallo" of Afrikaans to "óla" in Tetum, a reminder of Portuguese influence in Timor-Leste. Many such words appear to function as both introduction and identity marker. But, says Professor Duranti, it's not quite that simple.

"It's hard to go straight from the use of a particular greeting to a national character, even though it is tempting," he tells the BBC. Alternative or secondary greetings, Duranti suggests, may offer better clues. "In English, given the common use of 'how are you?', there is an apparent interest in people's wellbeing." In some Polynesian societies, he adds, greetings are less about a word-for-word "hello" than about checking in on someone's plans or movements – literally asking "where are you going?". Greek, meanwhile, uses "Γειά σου" (pronounced "yah-soo") as a typical informal greeting, offering a wish for health rather than a simple salutation. It is also usable for "goodbye".

Other languages also turn abstract concepts into multipurpose greetings that serve as both "hi" and "bye". "Ciao" comes from a Venetian dialect phrase meaning "at your service", and the French "salut" is an informal expression used for both greeting and parting company. Similarly, the Hawaiian "aloha" can express affection or compassion, and the Hebrew "shalom" peace or wholeness. Yet, as Duranti cautions, even these evocative examples shouldn't be viewed as cut-and-dry indicators of national character.