We can write each letter of the English alphabet as a small letter (abc...) or as a large or capital letter (ABC...). Here is a full list of capital letters.
In English, we do NOT use capital letters very much. We use them mainly for the first letter of sentences, names, days and months as well as for some abbreviations. We always write the first person pronoun as a capital I.
It is not usual to write whole sentences in capitals. A sentence or paragraph written in capitals is very difficult to read. Did you ever see a book written in capital letters? Of course not! We cannot easily read lots of text in capital letters. Lawyers, for example, know that capitals are difficult to read and that is why they often write contracts in capital letters!
When do we Use Capital Letters?
1. Use a capital letter for the personal pronoun 'I':
What can I say?
2. Use a capital letter to begin a sentence or to begin speech:
The man arrived. He sat down.
Suddenly Mary asked, "Do you love me?"
3. Use capital letters for many abbreviations and acronyms:
G.M.T. or GMT (Greenwich Mean Time)
N.A.T.O. or NATO or Nato (North Atlantic Treaty Organization)
4. Use a capital letter for days of the week, months of the year, holidays:
5. Use a capital letter for countries, languages & nationalities, religions:
6. Use a capital letter for people's names and titles:
Anthony, Ram, William Shakespeare
Professor Jones, Dr Smith
Captain Kirk, King Henry VIII
7. Use a capital letter for trade-marks and names of companies and other organizations:
Pepsi Cola, Walkman
Microsoft Corporation, Toyota
the United Nations, the Red Cross
8. Use a capital letter for places and monuments:
London, Paris, the Latin Quarter
the Eiffel Tower, St Paul's Cathedral
Buckingham Palace, the White House
Oxford Street, Fifth Avenue
Jupiter, Mars, Sirius
Asia, the Middle East, the North Pole
9. Use a capital letter for names of vehicles like ships, trains and spacecraft:
the Orient Express, the Flying Scotsman
Challenger 2, the Enterprise
10. Use a capital letter for titles of books, poems, songs, plays, films etc:
War And Peace
Like a Virgin
The Taming of the Shrew
The Lion King, Gone With The Wind
11. Use capital letters (sometimes!) for headings, titles of articles, books etc, and newspaper headlines: