Just as there are many different spoken languages, there are also many different sign languages. American Sign Language is the one used in the United States and several other countries. Hundreds of thousands of people communicate using this language.
Just like spoken language, sign language can be used to express all kinds of thoughts, not just to name things. Sign language can also be used to talk about actions, feelings, and ideas. One difference between sign language and spoken language is that sign language can express more than one meaning at a time. Spoken language expresses thoughts one word after another, but sign language uses facial expressions and body movements to add additional ideas to the main one expressed by a hand sign.
One form of sign language that many people recognize is the manual alphabet, or finger spelling. This type of sign language, however, is used mainly for proper names. It may also be used for unusual or technical vocabulary words. With finger spelling, a word is spelled out letter by letter, using a different hand sign for each letter of the alphabet.
You can search online and find charts of the hand positions for the letters of the alphabet and videos that show the signs in more detail. Finger spelling should be done with your dominant hand - your right hand if you are right-handed or your left hand if you are left-handed. For most signs, the palm of the hand should face outward toward the person to whom you are signing. Most letters are signed holding the hand still, but a few like j and z are signed by moving the fingers.
Most words in sign language are not spelled out letter by letter. Instead they are expressed by a single sign. As with finger spelling, most words are signed with the dominant hand, palm outward. Some words are signed with both hands.