Learn Hardcore Swedish: Han lovar att ringa mig imorgon.

Here it introduces a verb in the infinitive: att ringa = “to call”.
English: He promises to call me tomorrow.
Swedish usually uses att + infinitive after many verbs:
- börja att läsa – “to start to read”
- försöka att förstå – “to try to understand”

The att that means “that” (introducing a subordinate clause) is different in function, even though it looks the same in writing.
Example of “that”-att:

Han säger att han är trött. – “He says that he is tired.”
Here att is followed by a full clause (han är trött), not just an infinitive verb.

Why is it ringa and not ringar?

Ringa is the infinitive form (“to call”). After att, Swedish uses the infinitive:

att ringa – “to call”
att äta – “to eat”
att sova – “to sleep”

Ringar is the present tense:

Han ringer mig. – “He calls me / He is calling me.”

In the sentence:

Han lovar att ringa mig imorgon.
→ lovar is the finite verb (present tense)
→ att ringa is an infinitive phrase (“to call”)

Why is it mig and not jag?

Because mig is the object form of “I”.

jag = “I” (subject form)
mig = “me” (object form)

You use jag as the subject of a verb:

Jag ringer honom. – “I call him.”

You use mig as the object, when someone does something to you:

Han ringer mig. – “He calls me.”
Han lovar att ringa mig. – “He promises to call me.”

So mig here is the person receiving the call.

Why do you say ringa mig and not something like ringa till mig?

With the verb ringa (“to call / to phone”), Swedish can:

Take a direct object:
- ringa någon – “call someone”
  - Han ska ringa mig. – “He will call me.”
Or use ringa till någon (“call to someone”), which is also correct but a bit more explicit or formal:
- Han ska ringa till mig.

Everyday Swedish very often uses the direct-object pattern (ringa mig, ringa honom, ringa mamma), so ringa mig is the most natural here.

You don’t need anything like English “call up me” – just ringa mig.

Is lovar att ringa like “promises that he will call” in English?

Yes, that’s a good way to think of it.

Literal structure: He promises to call me tomorrow.
Natural English paraphrase: He promises that he will call me tomorrow.

Swedish uses att + infinitive:

lovar att ringa – “promises to call”
lovar att komma – “promises to come”

If you really wanted to mirror the English “that he will call”, you could say:

Han lovar att han ska ringa mig imorgon. – “He promises that he will call me tomorrow.”

But in most situations Han lovar att ringa mig imorgon is shorter and more natural.

How does Swedish express the future here? There is no “will” or “going to”.

Swedish often uses present tense to talk about the future, especially when the context makes the time clear:

Han ringer mig imorgon. – “He will call me tomorrow.”
Vi ses på måndag. – “We’ll see each other on Monday.”

In Han lovar att ringa mig imorgon:

lovar is present tense (“promises”), but the content of the promise clearly refers to the future because of imorgon (“tomorrow”).

You can also use more explicit future forms:

Han ska ringa mig imorgon. – “He is going to call me tomorrow.”
Han kommer att ringa mig imorgon. – “He will call me tomorrow.” (more neutral/factual)

But here, the idea of future is mainly carried by imorgon and the meaning of promising.

Where can I place imorgon? Is Han lovar att ringa mig imorgon the only correct word order?

Other word orders are possible, and they’re often used:

Han lovar att ringa mig imorgon.
Han lovar att imorgon ringa mig. (possible but sounds a bit unusual/marked)
Imorgon lovar han att ringa mig. – “Tomorrow he promises to call me.”

General tendencies:

Time adverbials like imorgon commonly go at the end:
- Han ringer mig imorgon.
You can put imorgon at the beginning for emphasis on the time:
- Imorgon ringer han mig.

In the original sentence, imorgon naturally goes at the end of the whole phrase att ringa mig imorgon.

Can I say Han ska lova att ringa mig imorgon?

Grammatically it’s possible, but it sounds strange in most contexts.

Han lovar att ringa mig imorgon. – “He promises to call me tomorrow.” (normal)
Han ska lova att ringa mig imorgon. – “He is going to promise to call me tomorrow.”
→ This literally means he will perform the act of promising in the future, which is odd.

Usually you either talk about:

The promise now:
- Han lovar att ringa mig imorgon.
Or the future action itself:
- Han ska ringa mig imorgon.

So stick with Han lovar att ringa mig imorgon for “He promises to call me tomorrow.”

Is there any difference between imorgon and i morgon?

They mean the same thing: “tomorrow”.

imorgon – written as one word; this is now the most common modern spelling.
i morgon – written as two words; still correct and seen in some texts.

In speech there is no difference; they are pronounced the same. As a learner, you can safely use imorgon.

How would this sentence change if I were the one making the promise?

You only need to change the subject pronoun and the object pronoun:

Han lovar att ringa mig imorgon.
→ “He promises to call me tomorrow.”

If you promise to call him:

Jag lovar att ringa honom imorgon.
- Jag – “I” (subject)
- honom – “him” (object)

If you promise to call you (speaking to someone):

Jag lovar att ringa dig imorgon. – “I promise to call you tomorrow.”