Ninapaswa kupiga simu kwa dada yangu leo jioni.

Ninapaswa can be broken down as:

• ni- = I
• -na- = present tense
• -paswa = be supposed to / ought to / should

So ninapaswa means something like I should, I ought to, or I am supposed to.

Depending on context, it can sound a little stronger than English should, but should is usually a good translation.

After a verb like ninapaswa, the following verb usually stays in the infinitive form, which begins with ku-.

So:

• kupiga = to call / to hit / to strike
• kupiga simu = to make a phone call

This is similar to English I should call, where call comes after should. In Swahili, that second verb is normally marked with ku-.

Literally, kupiga often means to hit, to strike, or to beat. But in many common expressions, it has a more idiomatic meaning.

So kupiga simu is a fixed expression meaning:

• to call
• to make a phone call

It is not understood literally here.

Here, kwa marks the person receiving the call, so it works a bit like to in English.

So:

• kupiga simu kwa dada yangu = to call my sister
  or more literally
• to make a phone call to my sister

English says call my sister without to, but Swahili often uses a structure closer to call to someone in this kind of phrase.

• dada = sister
• -angu = my

In this phrase, the possessive appears as yangu, so:

• dada yangu = my sister

This is a very common way to show possession in Swahili: noun + possessive.

Not always.

Dada can mean:

• your actual sister
• a female sibling in a broader family sense, depending on context
• sometimes even sister in a social or respectful sense when addressing or referring to a woman

In this sentence, though, learners will normally understand it as my sister.

Swahili does not use articles like English a, an, and the.

So simu does not need a separate word for a phone or the phone. The meaning is understood from context.

In kupiga simu, the whole expression simply means to call or to make a phone call.

Literally, leo jioni means today evening.

The most natural English translation is usually:

• this evening

In some situations, English tonight may also fit, especially if you mean later today. But jioni is specifically evening, while usiku is night.

No, not completely.

The sentence as written is natural:

• Ninapaswa kupiga simu kwa dada yangu leo jioni.

But the time expression can also move:

• Leo jioni ninapaswa kupiga simu kwa dada yangu.

Both are fine. Swahili often allows this kind of flexibility, especially with time words like leo, kesho, and jana.

You mainly change the tense part inside ninapaswa:

• Nilipaswa kupiga simu kwa dada yangu leo jioni. = I was supposed to call my sister this evening.
• Nitapaswa kupiga simu kwa dada yangu leo jioni. = I will have to / I will need to call my sister this evening.

So the key tense changes are:

• ni-na-paswa = I should / I am supposed to
• ni-li-paswa = I was supposed to
• ni-ta-paswa = I will have to