Learn Hardcore Japanese: tantousya ni sugu renrakusite mo ii desu ka? - May I contact the person in charge right away?

Correct: 担当者に連絡する (contact the person in charge)
Also correct: 担当者に連絡をする (same meaning; uses the noun + する style)
Incorrect: 担当者を連絡する (you can’t mark the recipient with を here) Using へ is possible in some written contexts (e.g., signs: 〜へお問い合わせください), but に is the natural choice in conversation.

What is the も doing in 連絡してもいいですか? It doesn’t mean “also,” right?

Right. Here も is part of the set grammar V‑て(も)いい, which means “it’s okay/allowed to do V.” So 連絡してもいいですか asks for permission: “Is it okay if I contact (them)?”

Permission: V‑て(も)いい
Prohibition: V‑てはいけません / V‑ちゃいけません (casual)

Why is the verb in the て‑form (して)?

Because the permission pattern is V‑て + も + いい. You take 連絡する, make the て‑form 連絡して, then add もいい: 連絡してもいい.

How polite is this? Are there more or less formal alternatives?

Casual: 担当者にすぐ連絡してもいい？
Polite (neutral): 担当者にすぐ連絡してもいいですか。
Softer/more polite: …いいでしょうか／…よろしいでしょうか。
Very polite/humble (business): ご担当者様に今すぐご連絡差し上げてもよろしいでしょうか。 or 今すぐ連絡いたしてもよろしいでしょうか。

What’s the nuance difference among すぐ, すぐに, 今すぐ, 早速, and 直ちに?

すぐ: soon/right away; default adverb. Flexible.
すぐに: same meaning, slightly crisper/explicitly temporal; often preferred in formal writing.
今すぐ: right this instant (adds “now” emphasis).
早速: promptly/without delay; formal/business‑like, not always literally immediate.
直ちに: immediately, with urgency (official/imperative tone).

Where can すぐ go in the sentence? Are there word‑order options?

Both are natural:

すぐ担当者に連絡してもいいですか。
担当者にすぐ連絡してもいいですか。 Don’t put すぐ after も (e.g., 連絡してもすぐいいですか)—that’s ungrammatical here. すぐ should modify the contacting action.

Can I drop も and say 連絡していいですか?

Yes. V‑ていい is common in speech and means the same. V‑てもいい can sound a bit more careful/standard. In formal contexts, prefer …てもよろしいですか.

Why is it いいですか and not できますか?

いいですか asks for permission: “Is it okay if I…?”
できますか asks about ability/feasibility: “Can (someone) do it?” or “Is it possible?” So 連絡できますか means “Can (you/I) contact (them)?” not “May I contact (them)?”

Who is the subject here? Where is “I”?

Japanese often omits the subject when it’s clear from context. Here it’s implicitly “I.” If you need to be explicit: 今、私が担当者にすぐ連絡してもいいですか。 Usually, you don’t need 私 in conversation.

What exactly does 担当者 mean? Are there other ways to say it?

担当者 = the person in charge/responsible contact. Common alternatives:

担当の方 (polite, everyday)
ご担当者様 (very polite; used in letters/emails when you don’t know the name)
Referring to your own colleague humbly: 担当の者

Is it okay to say ご担当者様にすぐ連絡してもいいですか?

Grammatically yes, but nuance matters:

In emails/letters: ご担当者様 is standard.
In spoken conversation, especially if you’re talking about someone in the other company, say ご担当の方. Using 様 mid‑conversation can feel letter‑like.

What’s the difference among 連絡する, 連絡を取る, and 連絡を入れる?

連絡する: general “to contact.”
連絡を取る: to get in touch/establish contact (often implies two‑way connection).
連絡を入れる: to give a quick notice/call/text (you initiate; businessy and practical).

How do I make a negative/prohibitive version?

Prohibition: 担当者に連絡してはいけません。 (You must not contact…)
Request not to: 担当者に連絡しないでください。
Asking if you should refrain: 担当者に連絡しないほうがいいですか。

How do I ask about past permission, like “Was it okay that I contacted them right away?”

すぐ連絡してもよかったですか。
If you already did it and are checking: 先ほどすぐ連絡してしまいましたが、よろしかったでしょうか。 (very polite)

Can I use へ instead of に (e.g., 担当者へ連絡する)?

に is standard with 連絡する. へ sometimes appears in written notices or when addressing letters/messages, but with a person in everyday speech, に sounds most natural.

Any writing tips for すぐ and いい/良い?

すぐ is usually written in kana. The kanji 直ぐ exists but is uncommon in modern writing.
いい is typically written in kana. 良い is fine in formal writing, but in set phrases like 〜てもいい, kana いい is standard.