Emphatic exclamation expressing emotion e.g. Oh, No, Go away, OK etc.

Content words referring to people, places, things, qualities, or actions e.g. house.

The concept of quantity involving zero and units

Representation of people or scenes in the form of a print using a camera

Function words used in place of nouns or noun phrases e.g. we.

Query to get information e.g. what, which, when, where, who, whom, whose, why, whether and how. 

May be pictographic, but they can be anything that represents something else, usually a concept. 

Words of something written, a label, phrase, sentence etc

Words that indicate an action, occurrence, or state of existence e.g to walk, happen or be.

A listing of the words used for language