If you want to take respiratory medicine in the United States, you would use a nebulizer. But if you want to take respiratory medicine in Australia, you’d use a nebuliser.

Have you ever wondered why the various English-speaking countries can’t agree on how to spell their words?

Well, back before the 18th century English spellings weren’t standardized (or if you prefer, standardised). Then dictionaries started coming out, and different regions of the world adhered to different ones. Americans preferred Noah Webster’s dictionary. The British preferred Samuel Johnson’s.

Many of the spelling differences happened on purpose. Webster believed in reforming spelling for largely nationalistic reasons. Some of his spelling innovations caught on while others, such as changing “tongue” to “tung” never did.

A few of the most noticeable spelling differences between regions are—

-or vs. -our

In America, the spellings for unstressed -our endings were changed to -or. Colour became color, honour became honor and so on. But for stressed -our endings such as contour or troubadour, Americans kept the “u.” The “u” has been dropped in some British words too, such as governor, mirror, and horror.

-er vs. -re

Most English words ending in -er once ended in -re. In the British English -re spelling is still used for several words such as centre, metre and theatre which were all changed to -er in the States. However, several British words were also changed to -er such as chapter, enter and months such as October, November and December.

-ize vs. -ise

And now we come to the one that affects our good friend the nebulizer (or nebuliser). Americans always use the -ize ending, for example organize, realize and of course nebulizer. British spelling uses either -ize or -ise. The Oxford English Dictionary insists on the -ize spelling. However, -ise is still commonly used in the UK at a ratio of about 3:2. Both spellings are also used in Australia and New Zealand, but there the use of -ise is much more common at a ratio of 3:1.

So there you have it. That’s why some people use a nebulizer while (or whilst) others prefer a nebuliser.