We'll start with something basic. This is a biggie, because almost every sentence has one: the subject. It's the word or phrase that performs the action in a sentence. ("Action" here is being used loosely; many sentences have nothing we'd typically call "action." Another way of putting it is that the subject is the word or phrase that does the "doing" or "being" in a sentence, whatever that doing or being may be.) To get all grammar-splainy here, subjects are technically nouns, noun phrases, or pronouns. Here are some subjects being subjects, but in bold:
I hear yodeling.
The yodeling is coming from over there.
Information about grammar can apparently be yodeled.
Those grammarians are excellent yodelers.
There is another yodeling grammarian.
We are surrounded by yodeling grammarians.
Note that the subject usually comes first. In the fifth sentence, though, it comes after the verb is. This is because the there at the beginning of the sentence is really just a place holder.
Note too that not every sentence has a visible subject. In the last sentence, there is an understood (and, in this case, desperately hoped-for) subject that is "you" (or "someone" or "anyone").
The word predicate has two grammar-related meanings. One is simple, and that's the one we're treating here. Predicates are usually everything in a sentence or clause that's not the subject. (A clause is a part of a sentence that has its own subject and verb.) They express what is said of the subject, and usually consist of a verb and other stuff that's not the subject. Here are some predicates in bold:
I had a dream about those yodeling grammarians last night.
People who are not grammarians yodel too, but I don't dream about them.
Here come yet more yodeling grammarians.
Please don't yodel anymore, grammarians.
The predicate is often much bigger than the subject. As the second sentence shows, though, it can be smaller. If clauses are joined by a conjunction like but, or, and, or although, the conjunction isn't part of the predicate.
If you're interested enough in grammar to have made it this far, you likely feel pretty confident about your understanding of what nouns and verbs are. Both are super important, though, so we'll review them here anyway.
Teachers often tell us that a noun is a person, place, or thing. That's mostly right. A more nuanced definition is that a noun is a word that refers to a thing (book), a person (Noah Webster), an animal (cat), a place (Springfield), a quality (softness), an idea (justice), or an action (yodeling).
You may think of verbs as "action words" but that too is a little oversimplified. Verbs can express an action (yodel), an occurrence (develop), or a state of being (exist). They're often the grammatical center of the predicate and typically have full descriptive meaning and characterizing quality—except when they don't; some verbs really only serve to connect, like the is in Grammar is complicated.
Verbs have multiple forms. The basic form is called the infinitive. It's the stripped-down form like, yodel or flee.
Nouns and verbs often go about with other word-friends. Sometimes they form noun phrases or verb phrases. Such phrases can do a lot of the same things that nouns or verbs alone can do. To qualify as a noun or verb phrase, a group of words must: express a single idea; function as a single part of speech; not include both a subject and a predicate. Noun phrases refer to one of the things nouns refer to and answer the question "What?" or "Who?" Verb phrases express what verbs express: an action, occurrence, or state of being.
MORE VERB TERMS: Verbs are more complicated than they look
A pronoun is a word that is used instead of a noun or noun phrase. Pronouns refer to either a noun that has already been mentioned or to a noun that does not need to be named specifically.
The most common pronouns are the personal pronouns. These refer to the person or people speaking or writing (first person), the person or people being spoken to (second person), or other people or things (third person). Several of the personal pronouns have singular and plural forms. Like nouns, personal pronouns can function as either the subject of a verb or the object of a verb or preposition. Most of the personal pronouns have different subject and object forms.
Here are some personal pronouns in bold:
I hear the grammarians yodeling again.
They have been yodeling since noon.
Do you think he or she can make them stop?
We have had problems with yodeling grammarians before.
While the subject performs the action (or does the doing or being) in a sentence, an object is on the receiving end. There are two main kinds of objects: direct and indirect. Direct objects are more common. They indicate the person or thing that receives the action of a verb:
The grammarians are yodeling a song about nouns.
In this sentence, the direct object is a song about nouns. It receives the action of are yodeling; it answers the question "What are the grammarians yodeling?"
An indirect object can only occur if there's already a direct object, and it only occurs after some verbs. An indirect object indicates the person or thing that receives what is being done or given—that is, who or what is on the receiving end of the direct object. It comes between the verb and the direct object:
I gave the yodeling grammarians a dirty look, but they kept yodeling.
"A dirty look" is the direct object because it's the thing that's given. "The yodeling grammarians" is the indirect object because the yodeling grammarians are the ones who receive the dirty look that's given.
Plenty of sentences don’t have either kind of object:
Yodeling grammarians are a dime a dozen these days.
Although the phrase "a dime a dozen" comes right after the verb—which is definitely direct and indirect object territory—the phrase does not receive the action of the verb are.
There's a third kind of object we haven't mentioned yet: the object of a preposition. More on those below, in the part about prepositions.
Prepositions show direction, location, or time, or introduce an object. They are usually followed by an object—a noun, noun phrase, or a pronoun. The most common prepositions are little and very common:
at, by, for, from, in, of, on, to, with
Also common are:
about, above, across, after, against, along, among, around, because of, before, behind, below, beneath, beside, between, close to, down, during, except, inside, instead of, into, like, near, off, on top of, onto, out of, outside, over, past, since, through, toward, under, until, up, upon, within, without
Prepositions typically show how the noun, noun phrase, or pronoun is related to another word in the sentence.
a grammarian friend of mine
the grammarian with the fierce yodel
assaulted by someone who was sick of hearing yodeling
everyone except that yodeling grammarian
Prepositions with their objects form prepositional phrases.
A gerund is a kind of noun that looks suspiciously like a verb. Gerunds end in -ing, just like the present participle of a verb (i.e., an -ing verb; don't worry, we'll get to that one). In fact, you can't tell the difference between a gerund and an -ing verb until you see it in action. If it's a gerund, it'll be acting like a noun, as in these examples:
Yodeling is not all those grammarians can do. (Yodeling is the subject of the sentence.)
Don't pretend you're not impressed by their yodeling. (Yodeling is the object of the preposition by.)
Almost all verbs have two important forms called participles. Participles are forms that are used to create several verb tenses (tenses show when an action happened); they can also be used as adjectives.
The present participle always ends in -ing; it's the form that looks just like a gerund: yodeling, remembering, going. The past participle usually ends in -ed (yodeled, remembered), but there are plenty of exceptions to that rule, such as forgotten and gone. (The past participle is usually the same as the plain old past tense (yodeled, remembered), but not always: forgot, went.)
As we said above, a participle can also be used as an adjective (that is, to describe a noun or pronoun). A present participle (an -ing word) describes the person or thing that causes something; for example, an invigorating yodel is one that invigorates. A past participle (usually an -ed word) describes the person or thing who has been affected by something; for example, an invigorated person is one who has been affected by invigoration. Or good yodeling.
Too much is never enough! Get more grammar tips at 8 More Grammar Terms You Used to Know: Special Verb Edition.