The difference is mainly the vocabulary. Also some words are spelled differently. Words ending in -or in american english would end in -our in british english. For example, "Color " would be " Colour " in Britain. Vocabulary would be similar but not completely different. For example, " Airplane " in America would be " Aeroplane " in Britain Dont worry about trying to learn both because they are both the same language, though there just used differently. Hope I helped.

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