I. 0mission of a particle

When speaking informally, the particles wa, ga, o and ni are often omitted.
0mission of these particles results in a subtle change of meaning. You are advised not to omit any particles while you are trying to learn to speak Japanese.

Examples
1. Kore (wa) ikura desu ka.
"How much is this?"
2. Sono shatsu (wa) momen desu ka.
"Is that shirt cotton?"
3. Watashi (ga) ikimasu yo.
"I will go."
4. Kore (o) kaimashita.
"I bought this."