When does a comma 、replace a particle?

Question

When a particle is omitted in casual speech, the written representation (to my great surprise) adds a comma. Do these commas actually correspond to any change or pause in the intonation?

テニス、する？ 今、何、してる？ どんな食べ物、好き？

Also, are these commas required or optional?

EDIT:

The source of this information is the textbook「上級へのとびら」. While there is no direct statement in the book that the commas act as a replacement for the omitted particles, in the multiple example sentences as well as in a table of examples for several levels of speech, the comma 「、」 is in fact used as a replacement for the omitted particles in every case.

Example dialog:

A: 「あ～、お腹、すいたなあ」

B: 「俺{おれ}も腹へった。この辺にうまいトンカツの店があるんだぜ。食{く}いに行こうか。おごるよ」

A: 「いやよ、トンカツは。カロリーが高いから」

B: 「なんだ、じゃ、俺{おれ}、一人で行こうっと」

A: 「あ、まって！　その店、おいしいんでしょ。やっぱり、私も行くわ！」

B: 「じゃ、今から行くぞ！」

(You can hear the example dialog in this official audio transcript, from the minute 3:30)

Table of examples for each level of speech (see the third column くだけた言い方):

Unfortunately, there is no audio transcript for the contents of the table above.

Answer 1

All the commas in your image are not required at all. Rather, they are usually avoided. The following sentences are just fine:

• あの人先生？
• その映画面白い？
• 何かスポーツする？
• 今弁護士してる。
• これ見て。

Forget the idea that a comma "replaces" a particle; it never does. Commas in Japanese play little semantic role, and they are typically nothing more than reading aids. They are typically used after conjunctions (e.g., じゃ) and interjections (e.g., あ～), but even this is not a hard rule. In the pasted image, commas are used much more often than usual, but that's probably because the author thought they could help beginner readers to parse those sentences.

Answer 2

The premise that when a particle is omitted the written representation adds a comma is not true. Some of the commas in your example sentences are actually akward:

テニス、する？ 〇

今、何してる？ 〇

今、何、してる？　☓

どんな食べ物、好き？ ☓

The comma accounts for an actual pause in the intonation as one would naturally expect, and it does not have a grammatical function in general. For this reason, 何、してる does not make sense, it should be either 何をしてる or 何してる.

Perhaps if you share the source that specifies that the commas are placed to represent the abscence of a particle we can better understand the purpose behind this, in my opinion, false claim.

EDIT:

After adding the detailed materials from the source, this is what I found out. In the example dialog, some of the commas do come with a pause, but others don't. Pay attention to the first sentence (minute 3:30):

あ～、お腹[が]、すいたなあ (3:30, が is omitted)

There is no pause between お腹 and すいた, which does not support my point of view, but rather the idea that the comma is only being used as a replacement for が, in this case. In other instances, notably when the omitted particle is は, we can actually hear a pause in the example dialog:

なんだ、じゃ、俺{おれ}[*は]、一人で行こうっと (3:44, は is omitted)

あ、まって！　その店[は]、おいしいんでしょ。やっぱり、私も行くわ！ (3:48, は is omitted).

So, there is a mixture of commas that represent and actual pause and commas that don't.

I stick to my guns and still think that some of this commas are not natural at all. It might be possible that using commas to replace omitted particles is a regular practice to some extent, but I can't answer that. I am looking forward to listen to what the more experienced Japanese speakers and native speakers have to say.