Learn Hardcore Japanese: atarasii nikki wo katte, maiban nihongo de itigyou dake kakukoto ni simasita. - I bought a new diary and decided to write just one line in Japanese every night.

新あたらしい　日記にっき　を　買かって、　毎晩まいばん　日本語にほんご　で　一行いちぎょう　だけ　書かくこと　に　しました。atarashii nikki o katte, maiban nihongo de ichigyou dake kakukoto ni shimashita.

I bought a new diary and decided to write just one line in Japanese every night.

Breakdown of atarashii nikki o katte, maiban nihongo de ichigyou dake kakukoto ni shimashita.

をo

direct object particle

Questions & Answers about atarashii nikki o katte, maiban nihongo de ichigyou dake kakukoto ni shimashita.

Why is 買って in the て‑form instead of 買いました?

The て‑form 買って is used to link actions in sequence:

新しい日記を買って、…しました。
→ “(I) bought a new diary, and then (I) … decided.”

Japanese often uses the て‑form where English would use “and” or “and then.”
If you said:

新しい日記を買いました。毎晩日本語で一行だけ書くことにしました。

that would be two separate sentences. Using 買って smoothly connects them into one flow: “I bought a new diary and decided to…”

There’s no “I” in the sentence. How do we know it means “I” decided?

Japanese often omits the subject when it’s obvious from context.

In this sentence:

新しい日記を買って、毎晩日本語で一行だけ書くことにしました。

the decision 書くことにしました (decided to write) is clearly something the speaker does about their own diary and their own study habit. So the understood subject is “I”.

You could explicitly add it:

私は新しい日記を買って、…書くことにしました。

but in natural Japanese, especially about your own plans, 私は is usually dropped unless you need contrast or emphasis.

What does 日本語で mean here? Why use the particle で?