I have a general grammar question. I often see the term copula as it is like different from what a normal verb is.
According to one of my references Basic Korean: A Grammar and Workbook by Andrew Sangpil Byon:
In English, copulas “am,” “are,” and/or “is” can express at least two things. First, they are used to indicate the equational expression (e.g., something equals something), as in “John is a student” or “Hyundai is an automobile company.” In addition, they indicate that something is located or existing as in “There are Korean people” or “Honolulu is in Hawaii.” In Korean, two different words express these two functions. For the equational expression, Korean has the copula 이다 (or 안이다 for negation). For the verb of existence or location, Korean has the verb 있다 (or 없다 for negation).
Am I right in saying that every copula is a verb but not every verb is a copula then? Is it correct to say that "copulas are verbs expressing equational expressions, location or existance"?
Are there other copulas apart from 이다/안이다 and 있다/없다 that are worth knowing?
Maybe this is a silly question but I just want confirmation as I see this term coming up a lot.