Noun-s vs. Verb-s: Key Grammatical Differences in English

In English, the ending -s appears in different places depending on whether the word is a noun or a verb. At first glance, this may look like a single, simple rule. In reality, many learners get confused because the reason for adding -s is not the same in each case.

The truth is that -s follows two completely different grammatical ideas: one for nouns and another for verbs.

In this article, we will look carefully at why and when -s is added, and how to tell these two rules apart.

Quick Summary

Reason for Adding -s to Nouns and Verbs

Adding -s to a noun or a verb is one of the most basic grammar rules in English. In everyday conversation, small mistakes with -s may not always block communication. However, in written English, especially in formal contexts, these errors stand out and can make a sentence sound careless or unpolished. That is why it is worth understanding how this rule actually works.

One important point to remember is that the reason for adding -s is not the same for nouns and verbs. Although the form looks identical, the grammar behind it is completely different.

In simple terms, the following rules determine when -s is required:

These two rules may look similar on the surface, but they serve different grammatical purposes. Let’s examine each one more closely.

Noun -s

This rule is straightforward. When you want to make a noun plural, you usually add -s to the noun.

For example, the plural of dog is dogs, and the plural of professor is professors. In the same way, most nouns form their plural simply by adding -s.

That said, this rule does not apply to every noun. Some nouns do not take -s, such as uncountable nouns, and others change form instead of adding -s, known as irregular nouns.

Uncountable Nouns

Uncountable nouns refer to things that are not counted as separate units. Because of this, they do not take a singular article (a or an), and they also do not take a plural ending like -s.

A common example is water. Since water is not counted as individual items, you cannot say a “water,“ nor can you add -s to make “waters“ in the usual sense.

Instead, uncountable nouns are often measured using expressions such as a glass of water or some water.

Irregular Nouns

Irregular nouns are a group of nouns whose plural forms are not made by simply adding -s. Instead, they change their form when they become plural.

For example, “medium“ is a singular noun, but its plural form is “media.“

Because the plural form is already built into the word itself, these nouns do not take -s.

Verb -s

While adding -s to a noun depends on whether the noun is singular or plural, adding -s to a verb follows a different rule and requires more careful attention.

As noted earlier, -s is added to a verb when the subject is a third-person singular noun.

Third-Person Singular Noun

In English, subjects are grouped into three perspectives: first person, second person, and third person.

• First-person noun: “I“
• Second-person noun: “you“
• Third-person noun: other than “I“ and “you.“

Among these, only a present-tense verb with a third-person singular subject takes the ending -s. This rule explains the difference between the two sentences below.

I want to study English.

Here, the subject “I“ is first-person singular, so the verb want does not take -s.

He wants to study English.

In this sentence, the subject “he“ is third-person singular. Because of that, -s must be added to the present-tense verb, changing want to wants.