Why should uppercase and lowercase letters be used in English?

The Latin alphabet used in English is derived from the Greek alphabet. Greek letters were originally all uppercase letters and no lowercase letters. Capital letters are drawn straight, without unbroken strokes. This font is suitable for carving but not for fast writing. Later, in the process of writing, in order to write quickly and conveniently, the strokes were sloppy, so that the letters gradually became rounded and elongated, and began to approach the current shape of lowercase letters. In order to avoid confusion, some letters have added strokes (such as the small dot on the i), and some have added additional decorative strokes (such as the hook on the right end of most letters, which is both decorative and can mark the boundaries of the letters) , so that a word written in continuous strokes will not look like a continuous, winding line and cannot be read. Some letters (such as c, v) are just smaller in shape. In this way, the shape of the lowercase letters is gradually finalized. At the same time, the shapes of some capital letters have also undergone certain changes, mainly for the convenience of writing (such as changing the right bend to the left bend).

This is the same as the seal script with curved strokes making it difficult to write quickly. In hasty writing, the strokes gradually become straight due to insufficient bending, which is the same as the official script. The "bent-straight" change Although the directions are opposite, the driving force for change is for the convenience and speed of writing.

The number of letters, additional symbols, upper and lower case usage rules, etc. of each language using the Latin alphabet are not exactly the same.

Capitalize the proper names of individual words in English and the first letter of each sentence. The first letter of the content word of a multi-word proper name must be capitalized. Most abbreviations should be capitalized.

These are used to give special marks and indicate special meanings to facilitate quick identification when reading. For example, some proper names have the same sounds and shapes as common nouns, but do not express the meaning of common nouns (but are the names of a specific person, place, thing, etc.). This can be marked by capitalizing the first letter. Capitalizing the first letter of a sentence can clearly mark the boundary between one sentence and one sentence, making it easier to divide a paragraph or article into one sentence and read it. (If they are all lowercase letters and piled together densely, it will look like a mess and it will be much more depressing). By capitalizing each content word of a proper name, you can tell at a glance that this is a proper name and not an ordinary phrase. Some abbreviations are not conspicuous if they are not expressed in capital letters, because some abbreviations are difficult to pronounce according to the letter combination rules, and some have the same spelling as ordinary words, but do not express the meaning of ordinary words. Marked with capital letters, people can know at once that this word has a special meaning and should be read with the letter sound (a few commonly used letter abbreviations can also be pronounced with the combination sound, such as radar (even without capital letters), NASA).

In short, the use of lowercase letters is for convenience (later it became the mainstay, so after the emergence of printing, lowercase letters were mainly used), while the use of uppercase letters is to mark special meanings, or to be eye-catching and powerful (such as signs, slogans, etc.).