Some Notes

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."
II. Response : Doomo
Doomo is the abbreviated form of "Doomo arigatoo gozaimasu."
The former is less polite than the latter and is used by a customer when he speaks to a clerk, or by a teacher to a student.

Example
Customer : Kore kudasai.
"I'll take this."
Clerk : Doomo arigatoo gozaimasu. 1,000 en gozaimasu.
"Thank you very much. It's 1,000 yen."
Customer : Doomo.
"Thanks."
Clerk : Doomo arigatoo gozaimashita.
"Thank you very much."

III. Full form of ja : De wa
In this text book, ja has used instead of de wa. However, ja is the contracted form of de wa. De wa is used in a more formal situation than the one in which ja
is used. De wa used in the fifth line from the top, Dialogue 6-2 means "then." Ja on the seventh line in the same dialogue also means "then."

Example
A : Kore wa watashi no de wa arimasen.
"This is not mine."
B : De wa kore wa.
"Then, how about this?"
A : Aa. Sore wa watashi no desu.
"Oh, that's mine."

IV. Interjection : Mmmm
Mmmm shows the speaker's negative feeling.

Example
Clerk : Kore wa ikaga desu ka.
"How about this?"
Customer : Mmmm.... Amari yoku arimasen.
"Well, this isn't so good."
Clerk : De wa kore wa ikaga desu ka.
"Then, how about this one?"
Customer : Aa, kore wa ii desu ne.
"Oh, this is fine."