Here's why:
* Writing systems: Some languages use writing systems that don't distinguish between uppercase and lowercase letters. Examples include:
* Chinese: Uses characters, not an alphabet.
* Japanese: Uses a combination of characters (kanji), syllabic scripts (hiragana and katakana), and sometimes the Latin alphabet (romaji).
* Arabic: Uses a script where letters change form based on their position in a word, but no distinct capital form exists.
* Historical reasons: Even languages that adopted the Latin alphabet (like English, Spanish, French) may have historically lacked distinct capital letters, developing them later.
* Modern trends: Some languages, like Korean, have recently adopted capital letters for certain uses, like names, titles, and headings, but not for general writing.
In conclusion: While capital letters are common in many languages, they are not a universal feature of writing systems.