Classifier in sign language is a signed word that represents a particular group of objects or referents. A classifier handshape may be incorporated with a movement, palm orientation, and/or location to convey rich information in a predicate.
For example, the classifier "horizontal 3-handshape" can represent an object in a group of vehicles such as car, truck, bicycle, motorcycle, submarine, etc.
Classifier: horizontal CL3 for a class of some vehicles.
The classifier is incorporated into a verb phrase. In some way, it functions like a pronoun in a verb phrase. Like pronouns, a noun must be signed before a classifier can be referred to.
There is no ASL without classifiers. Classifier predicates in ASL are very common and heavily used. Learning and understanding classifiers can significantly improve your expressive language skills.
Watch how different classifer handshapes are used for each of the objects on a table in the video below.
The ASL speaker first signs the noun and then the classifier predicate. She did first for the book. But for the rest of the objects, she didn't repeat the noun TABLE because she has established the reference and consistently refers to it. This gives you the idea how different classifiers are used for these objects.
Learn some common classifier handshapes that represent some classes of nouns.
The classifier of this upright index finger handshape (CL1) may represent a thin and/or tall object or a person, such as a person, a twig, a pole, a pen, a stick, etc.
Again, remember that a noun is first signed before its classifier can be used to represent its referent in a verb predicate.
The handshape looks like this image above but its palm orientation is horizontal, not upright. This classifier may represent a group of pieces such as an animal, chair, a toilet, a rocking chair, a sitting person, etc.
The classifier, using this handshape with the palm orientation facing down, is used to represent such objects as a picture, a paper, a table, a bed, etc.
Using a classifier is not limited to a handshape, but also can involve a location, a palm orientation, and/or a movement to convey more information.
The signer begins with the ASL word table [left image] and then assigns it a pronominal classifier (palm faced down) for the table. Notice that the signer uses the passive hand for the classifier because she uses the dominant hand for the next noun (cat).
The signer then utters the one-handed ASL word cat (the noun) and immediately assigns it a classifier. Notice that the signer still holds the passive-handed classifier for the table.
The bent-2 classifier represents the sitting cat. That is, in English, The cat is sitting below the table.
Or, "... sitting on the table".
Or, "... lying down on the table". The signer has changed the palm orientation of the classifier to represent a lying-down cat. If she lowers her eyelids at the same time she signs "lying down", it means the "the cat is sleeping on the table."
Learn and use classifiers in sentences as much as you can. The more you understand and comfortably use them, the more you enjoy this language. It also can significantly improve your expressive skills. ASL is vibrant and rich with classifiers.
Related post: a list of classifiers with examples
Also see depicting verbs.
Identify different classes of classifiers.