Different varieties of English often use different spelling conventions. If you have learned British or Indian English, for example, you will want to be aware of some of the more common spelling differences in American English. For example, words ending in –yse or –ise in British/Indian English (analyse, criticise) usually end in –yze or –ize in American English (analyze, criticize); words ending in –our in British/Indian English (labour, colour) usually end in –or in American English (labor, color); and words ending in –re in British/Indian English (theatre, centre) usually end in –er in American English (theater, center).