Footpath or sidewalk. Aluminum or aluminium. Gasoline or petrol, z or s when spelling words such as recognise/recognize. For people who grow up speaking less widely-used or standardised – sorry, standardized – variants, such as Australian or Irish, those minor differences mean switching between UK and US English is not usually a big deal. But to many Americans and British, some differences – such as saying “holiday” or “vacation” – can feel as vast as the Atlantic Ocean that separates them. According to linguists at the University of Vienna, people tend to see each other as “part of the same s…