Comparison of American and British English

American English and British English are the two main dialects (types) of the English language. American English is spoken in the United States, while British English is spoken in the United Kingdom. Both types of English are different to each other in some ways, for example in spelling, punctuation, grammar and vocabulary.
Spelling.
There are many words that sound the same in both American and British English but have different spellings, due mainly to the spelling reforms of Noah Webster. British English often keeps more traditional ways of spelling words than American English. For example:
Because some chemical elements have different spellings in American and British English, IUPAC has to use only one spelling of a word in their papers. For example:
Punctuation.
Punctuation is the name for the marks used in writing text. Punctuations, for example brackets/parentheses, full stops/periods, quotation marks/inverted commas, have different rules in American and British English.
Brackets/parentheses.
In British English, "( )" marks are sometimes called "brackets", "[ ]" are called "square brackets" and "{ }" are called "curly brackets". In formal British English and in American English, "( )" marks are "parentheses" (singular: parenthesis), "[ ]" are called "brackets" or "square brackets", and "{ }" can be called "curly brackets" or "braces". These marks are used in the same way in both dialects.
Quotation.
The rules on quoting a text is different in American and British English. In American English, " and ' are called "quotation marks". In British English, " and ' are called "inverted commas" or "speech marks". In American English, it is common to use the double quotation mark ( " ) in direct speech. In British English, it is common to use the single inverted comma ( ' ).