kyuukyuutai wo yobu.

It is read:

きゅうきゅうたい を よぶ

• 救急隊 = きゅうきゅうたい
• を = o (pronounced like お here)
• 呼ぶ = よぶ

So the full reading is きゅうきゅうたいをよぶ.

救急隊 refers to an emergency medical response team—the EMTs, paramedics, or emergency crew who come to help.

A useful nuance:

• 救急隊 focuses on the people/team
• 救急車 focuses on the ambulance vehicle

In everyday conversation, Japanese often uses 救急車を呼ぶ when someone would say call an ambulance in English.
So 救急隊を呼ぶ is understandable, but 救急車を呼ぶ is often more common in daily speech.

を marks the direct object of the verb.

Here:

• 救急隊 = the thing being called
• 呼ぶ = to call

So 救急隊を呼ぶ literally means to call the emergency team.

This is a very standard pattern:

• タクシーを呼ぶ = call a taxi
• 医者を呼ぶ = call a doctor
• 警察を呼ぶ = call the police

The dictionary form 呼ぶ is often used in example sentences, vocabulary lists, headings, and simple statement style.

Depending on context, dictionary form can mean things like:

• a basic action: call
• a habitual action: calls
• a future action: will call

In learning materials, it usually just shows the verb in its base form.

If you wanted other forms, for example:

• 救急隊を呼びます = polite
• 救急隊を呼んだ = called
• 救急隊を呼んで！ = call them!
• 救急隊を呼んでください = please call them

Not always. 呼ぶ means to call, but more in the sense of summon, send for, or have someone come.

So 救急隊を呼ぶ means to get the emergency team to come.
It does not focus on the physical act of using a phone.

That is why 呼ぶ is very natural with things like:

• 医者を呼ぶ = call for a doctor
• タクシーを呼ぶ = call a taxi
• 警察を呼ぶ = call the police

Yes, it is understandable and grammatical.

However, in many everyday situations, 救急車を呼ぶ is more common if the intended meaning is simply call an ambulance.

So the difference is roughly:

• 救急隊を呼ぶ = call the emergency responders/team
• 救急車を呼ぶ = call an ambulance

If you're speaking generally in an emergency, 救急車を呼んで！ is often the phrase learners hear most.

The spaces are just for learning purposes.

Normal Japanese is usually written without spaces, so this would normally appear as:

救急隊を呼ぶ。

Textbooks and beginner materials often add spaces to make the sentence structure easier to see.

By itself, 救急隊を呼ぶ。 in dictionary form sounds most like:

• a plain statement
• a note or instruction heading
• a description of an action

It does not sound like the most direct emergency command in conversation.

If you want a command, these are more natural:

• 救急車を呼んで！ = Call an ambulance!
• 救急隊を呼んでください！ = Please call the emergency team!
• 119番に電話して！ = Call 119!

So the plain dictionary form is often more neutral than urgent.

No, they are related but not the same.

• 救急隊 = emergency medical team / ambulance crew
• 救助隊 = rescue team
• 消防隊 = fire-fighting unit / fire brigade

In real life, these can all belong to the fire department system in Japan, but the words emphasize different roles.

So if the situation is specifically medical, 救急隊 is the right idea.
If you mean firefighters, use 消防隊 instead.

Sometimes particles get dropped in casual spoken Japanese, so you may hear something like 救急隊呼んで！

But for standard, correct Japanese—especially as a learner—you should keep を:

救急隊を呼ぶ
救急隊を呼んで！

Using the particle will make your Japanese clearer and more natural.