Determining Word Class

Every word in English belongs to one word class or the other. However, it is more important to know the functions of the word classes, as a noun may function as a verb in a context and vice versa. Let us study these examples:
The HOUSE is big( house here serves as a name and so it is a noun)

I HOUSE my friends( what do I do? The act of doing is a verb, so house here is a verb)
The HOUSE boy is handsome( which boy? Anything that tells you about a noun is an adjective, so house here is an adjective)

You do not need to know the words in the word classes or parts of speech; just know the functions of the word classes or parts of speech.