の（名詞化）
nominalizer の
The nominalizer の turns a verb or adjective clause into a noun phrase, “the act of doing” or “the fact that ...”. You attach の to the plain form, and the whole clause can then take particles like が or を, just like any noun.
For English speakers, it works much like “-ing”: 話す = “speak”, 話すの = “speaking”. This is different from the genitive の in 私の本 (“my book”), which connects two nouns to show possession.
1. Liking or disliking an activity
Words like 好き (like) and 上手 (good at) describe nouns, so to use them with an action, wrap the action in の first.
日本語を話すのが好きだ。
“I like speaking Japanese.”
- 日本語（にほんご）= Japanese (language)
- を = object marker
- 話す（はなす）= to speak
- の = nominalizer (turns “speak Japanese” into a noun)
- が = subject marker
- 好きだ（すきだ）= like
2. An action as the object of another verb
A clause wrapped in の can also take を and become the object of verbs like 待つ (wait), 見る (see), or 手伝う (help).
友達が来るのを待っています。
“I am waiting for my friend to come.”
- 友達（ともだち）= friend
- が = subject marker
- 来る（くる）= to come
- の = nominalizer
- を = object marker
- 待っています（まっています）= am waiting
Japanese also has the nominalizer こと, which often appears in the same role in more formal or written language. With verbs of direct perception such as 見る and 聞く, の is the natural choice.
How to form it
Plain form of verb/adjective + の (+ particle)
- 話す（はなす）= to speak → 話すの（はなすの）= speaking
- 泳ぐ（およぐ）= to swim → 泳ぐの（およぐの）= swimming
- 食べる（たべる）= to eat → 食べるの（たべるの）= eating
Key idea
The nominalizer の is a wrapper that makes a whole action behave like a noun, so it can be liked, watched, waited for, anything a noun can do.
Other N4 grammar
Updated .