You already know how to talk about actions you perform, like reading a book or eating sushi. But how do you say you can do something? That's where the potential form, or 可能形 (kanōkei), comes in. It changes a verb from "to do" into "to be able to do."

This form is essential for discussing abilities, skills, and possibilities. Whether you're talking about languages you can speak, food you can eat, or whether you can make it to a meeting, the potential form is your tool.

Creating the potential form depends on the verb group. As a quick reminder, Japanese verbs fall into three categories: Group 1 (u-verbs), Group 2 (ru-verbs), and irregular verbs. Each group has its own simple rule for conjugation.

Group 2 verbs are even simpler. These verbs end in いる (iru) or える (eru).

Finally, we have the two irregular verbs, which you just have to memorize.

The verb できる (dekiru) is incredibly common and often stands on its own to mean "can do" or "is possible."

When you use the potential form, there's a very important grammatical change to be aware of. The particle を (o), which marks the direct object of an action, often changes to が (ga).

Why? Because the focus of the sentence shifts. Instead of talking about doing an action to an object, you're talking about the ability itself. The thing that you can do becomes the subject of the potential ability.

Let's look at an example:

• 日本語を話します。(Nihongo o hanashimasu.)
  • I speak Japanese.

Here, the action is "speak" and the object is "Japanese." But when we change it to the potential form:

• 日本語が話せます。(Nihongo ga hanasemasu.)
  • I can speak Japanese.

The focus is now on the ability. "Japanese" is the thing that can be spoken by you. This shift from を (o) to が (ga) is a hallmark of the potential form.

There's another way to express ability in Japanese: by taking the dictionary form of a verb and adding 〜ことができる (koto ga dekiru). Literally, this means "the act of (verb) is possible."

So, what's the difference? The potential verb conjugations (like 読める) are much more common in everyday conversation. They're quicker, more natural, and the standard way to express ability.

〜ことができる is more formal and can be used to add emphasis or to define a specific ability, like on a resume. For example, 「日本語でビジネスメールを書くことができます」(Nihongo de bijinesu mēru o kaku koto ga dekimasu) sounds slightly more formal than 「書けます」(kakemasu) for "I can write business emails in Japanese."

In most daily situations, stick with the conjugated potential form.

Now, let's test your understanding of these forms.