They don't. They simply have different spellings for words from other countries such as the UK for example.
The correct spelling of the proper term is American.
proper English metre American spelling meter
The correct spelling of the proper noun (a Central American country) is Nicaragua.
The correct spelling of the proper noun is Argentina (a South American country).
No, difficulty is a common noun.
That is the correct spelling of the proper noun (Native American tribal name) "Wampanoag."
Spelling & Proper Grammar, for one.
That is the proper spelling, "thought" for the process of thinking.
That is the correct spelling of the word "proper" (correct, appropriate).The proper spelling is "proper" (correct, appropriate).
Probably about as many as use neither proper spelling nor proper grammar! Your question should say 'How many people out of 10 do not use proper punctuation?'
The US spelling is center but the spelling "centre" is frequently used for proper nouns such as buildings and towns.The UK spelling is centre.
Tires are referred to as tyres in the United Kingdom because that is the proper spelling on the word in the proper English language. American English often has misspellings of proper words.