Chinese characters are logograms used in the writing of Chinese and some other Asian languages. In Standard Chinese they are called Hanzi (simplified Chinese: 汉字; traditional Chinese: 漢字). They have been adapted to write a number of other languages including: Japanese, where they are known as kanji, Korean, where they are known as hanja, and Vietnamese in a system known as chữ Nôm. Collectively, they are known as CJKV characters. In English, they are sometimes called Han characters. Chinese characters constitute the oldest continuously used system of writing in the world. By virtue of their widespread current use in East Asia, and historic use throughout the Sinosphere, Chinese characters are among the most widely adopted writing systems in the world. 

Chinese characters number in the tens of thousands, though most of them are minor graphic variants encountered only in historical texts. Studies in China have shown that functional literacy in written Chinese requires a knowledge of between three and four thousand characters. In Japan, 2,136 are taught through secondary school (the Jōyō kanji); hundreds more are in everyday use. There are various national standard lists of characters, forms, and pronunciations. Simplified forms of certain characters are used in China, Singapore, and Malaysia; the corresponding traditional characters are used in Taiwan, Hong Kong, Macau, and to a limited extent in South Korea. In Japan, common characters are written in post-WWII Japan-specific simplified forms (shinjitai), which are closer to traditional forms than Chinese simplifications, while uncommon characters are written in Japanese traditional forms (kyūjitai), which are virtually identical to Chinese traditional forms. In South Korea, when Chinese characters are used they are of the traditional variant and are almost identical to those used in places like Taiwan and Hong Kong. Teaching of Chinese characters in South Korea starts in the 7th grade and continues until the 12th grade where 1,800 total characters are taught albeit these characters are only used in certain cases (on signs, academic papers, historical writings, etc.) and are slowly declining in use.
What is used to write Asian languages?
What kind?
Do they use them in Japanese?
What do they call them?
What are they in standard Chinese?
In Korean?
What do they use in Vietnam?
What are they referred to as in English?
How many Chinese characters are there?
How many should you know to be literate in Chinese?
How many forms are there?
Where do they use traditional characters?
What kind do they use in Malaysia?
What about in Hong Kong?
How many characters would you learn in a secondary school in Japan?
What is that group called?
Do they use more than that on a daily basis?
When do they start learning them in South Korea?
When do they stop?
How many do they learn?
characters
characters
CJKV characters
CJKV characters
yes
Japanese, where they are known as kanji,
kanji
kanji
Hanzi
Standard Chinese they are called Hanzi
hanja
 hanja
a system known as chữ Nôm
 a system known as chữ Nôm
Han characters
Han characters
the tens of thousands
the tens of thousands
between three and four thousand characters
requires a knowledge of between three and four thousand characters
There are various national standard lists of characters, forms, and pronunciations
There are various national standard lists of characters, forms, and pronunciations
In South Korea
In South Korea
Simplified forms of certain characters
Simplified forms of certain characters
A traditional variant
traditional variant and are almost identical to those used in places like Taiwan and Hong Kong. 
2,136
In Japan, 2,136 are taught through secondary school
the Jōyō kanji
the Jōyō kanji
yes
hundreds more are in everyday use
the 7th grade
Teaching of Chinese characters in South Korea starts in the 7th grade
the 12th grade
continues until the 12th grade where
1,800
where 1,800 total characters are taugh