Expressing Change: なる and する

In this section, you will learn several key sentence patterns such as Japanese potential, passive, and causative form. We express various things by conjugating verbs. Since you have already completed Japanese basic grammar, all you need to do is to memorize conjugation patterns. Here, you will learn how to express change.

Explanation for How なる and する Work

You can express change in Japanese by using the two words なる (intransitive) and する (transitive). As you learned in the previous lesson, intransitive verbs don’t have objects while transitive verbs have objects. We will show you several functions of なる and する, but please keep the basic concept in mind.

なる and する

Both なる and する can express change of states. The difference is that なる indicates your state alone will change like “to become” while する indicates someone will change your state like “to make it something.” The target of change is expressed by the particle に.

When you connect i-adjectives, you don’t add the particle に, but conjugate them: to replace い with く.

Here is a special expression. You can connect even verbs. However, verbs have to be the negative form. This doesn’t also require the particle に, but you need to replace the last い with く, that is to say, the same conjugation as the one for i-adjectives.

As you learned, ない, which is the negative form of “ある: to be, to exist,” is an exception. When you connect ない with なる and する, it will work differently from other verbs. In present and future tense, you need to drop る.

There is one common set phrase. When you use する with products, it means to order like “I will have coke.”

ようになる and ようにする

When you connect the affirmative form of verbs with なる and する, you need to apply another conjugation, which is ように. For the sake of simplicity, you may consider 運動うんどうをよくするように as a noun phrase. Just like the above, ようになる indicates that your state will change alone.

ようにする indicates someone will change your state and often expresses customary actions. With the above example, after that, it must be true that you continuously did exercises for a certain time. Depending on the contexts, it can imply your level of effort. For example, the third example below implies your effort while the fourth one doesn't. 

ようにする has another function, which is to make something happen. Unlike the first function, you took the action for just one time. With the example above, you maybe did something like opening a window.

ことになる and ことにする

The function here is to express decisions. ことになる indicates that decisions are naturally or situationally made, e.g. a teacher gives you a compulsory class. By contrast, ことにする indicates that decisions are made by you.

If you replace に with と, your speech will sound more formal.

You may wonder about how “決きめる: to decide” and “決きまる to be decided” work. They are the verbs which express decisions. You can just replace them.

ことにする is also interchangeable with ようにする which expresses customary actions. Note: you cannot use another function which is to make something happen. The following examples essentially have the same meaning.

In practice, even if you made a decision, you can use ことになる. When you have something that you would like to indirectly express, you can avoid disclosing who made the decision. For example, if you own a company and decide that the company will go bankrupt, you still say the following.

Summary

1. なる doesn’t have objects. Your state alone will change.
2. する has objects. Someone will change your state.
3. Nouns and na-adjectives require に to express targets of change.
4. I-adjectives and the negative form of verbs don't need に, but to replace い with く.
5. With the affirmative form of verbs, the conjugation is to add ように.
6. ことにする / なる expresses decisions.

We believe this topic is not too complicated. If you have difficulty understanding the concept, we recommend you review the lesson about transitive verbs and intransitive verbs. Then, if you would like to say “I’ve become able to speak Japanese,” how should it be? This sentence indicate change of your potential. Next, you will learn Japanese potential form.