1. Noun: This is the most common usage. It refers to a conversation between two or more people.
* Example: The *dialog* between the two characters was very realistic.
2. Verb: Less common, but it can mean to engage in conversation.
* Example: They *dialogued* for hours about their plans.
3. Adjective: This is also less common, and it means related to dialogue.
* Example: The play had a very *dialogical* style.
It's important to look at the context of the sentence to determine the correct part of speech for "dialog."