Tafadhali tumia bisibisi kukaza skrubu za kiti hiki.

A word-by-word breakdown is:

• Tafadhali = please
• tumia = use
  This is the imperative singular form of kutumia (to use).
• bisibisi = screwdriver
• kukaza = to tighten
• skrubu = screw / screws
• za = of / for, agreeing with the noun class of skrubu
• kiti = chair
• hiki = this

So the structure is roughly:

Please + use + screwdriver + to tighten + screws of this chair

Natural English: Please use a screwdriver to tighten the screws of this chair.

Because tumia is a command: Use!

In Swahili:

• kutumia = to use (the infinitive)
• tumia = use (imperative, singular)

So in this sentence, the speaker is telling one person to do something, so tumia is the right form.

If you were speaking to multiple people, you would normally say:

• tumieni = use (plural command)

So:

• Tafadhali tumia ... = Please use ... (to one person)
• Tafadhali tumieni ... = Please use ... (to more than one person)

Tafadhali makes the sentence polite. It means please.

Without it, tumia bisibisi... is still grammatical, but it sounds more direct:

• Tumia bisibisi... = Use a screwdriver...
• Tafadhali tumia bisibisi... = Please use a screwdriver...

It often appears at the beginning of a request, but Swahili word order can be somewhat flexible in conversation.

Kukaza is the infinitive to tighten. Here it expresses purpose:

• tumia bisibisi kukaza... = use a screwdriver to tighten...

So the pattern is:

• tumia X kufanya Y
• use X to do Y

In this sentence:

• tumia bisibisi = use a screwdriver
• kukaza skrubu... = to tighten the screws...

This is very natural Swahili.

Yes, but the meaning and structure would shift a little.

• Tafadhali tumia bisibisi kukaza skrubu...
  = Please use a screwdriver to tighten the screws...
• Tafadhali tumia bisibisi, kaza skrubu...
  = Please use a screwdriver, tighten the screws...

The version with kukaza links the second action as the purpose of using the screwdriver. That is why it fits very well here.

Because za agrees with the noun class of skrubu here.

Skrubu is usually treated like a class 9/10 noun. In many cases, class 9 and class 10 nouns look the same in singular and plural, so the form skrubu can mean either screw or screws, depending on context.

Here, the meaning is plural: the screws of this chair, so the possessive connector is:

• za = class 10 agreement

Compare:

• skrubu ya kiti hiki = the screw of this chair / a screw of this chair
• skrubu za kiti hiki = the screws of this chair

So za tells you that skrubu is being understood as plural.

Because in Swahili, demonstratives like this usually come after the noun.

So:

• kiti hiki = this chair
• literally: chair this

This is normal Swahili word order.

Also notice agreement:

• kiti belongs to noun class 7
• the class 7 form of this is hiki

That is why it is kiti hiki, not just one general word for this.

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

So a noun like bisibisi can mean:

• a screwdriver
• the screwdriver
• sometimes just screwdriver

The exact meaning depends on context.

Likewise:

• kiti hiki clearly means this chair
• skrubu za kiti hiki means the screws of this chair or simply screws for this chair, depending on context

English needs articles much more often than Swahili does.

It is a commonly used Swahili word for screwdriver, and like many tool and technology words in Swahili, it is not originally a very old native root.

Swahili has many borrowed or adapted words, especially for modern objects. That is very normal.

For a learner, the important thing is that bisibisi is a standard and useful word to know.

A simple pronunciation guide:

• Tafadhali = ta-fa-DA-li
• tumia = too-MEE-a
• bisibisi = bee-see-BEE-see
• kukaza = koo-KA-za
• skrubu = SKROO-boo
• kiti = KEE-tee
• hiki = HEE-kee

A few helpful points:

• Swahili vowels are usually very consistent:
  • a as in father
  • e as in bed but often a bit purer
  • i as in machine
  • o as in go but pure
  • u as in rule
• Stress is often on the second-to-last syllable:
  • tafaDHAli
  • bi si BI si
  • ku KA za

It is polite and natural, mainly because of tafadhali.

The command form by itself can sound direct:

• Tumia bisibisi... = direct instruction

Adding tafadhali softens it:

• Tafadhali tumia bisibisi... = polite request or instruction

So this sentence works well in everyday situations where you want to sound respectful but clear.

Yes, to some extent. Swahili has some flexibility, though not every order sounds equally natural.

The given sentence is very natural:

• Tafadhali tumia bisibisi kukaza skrubu za kiti hiki.

You may also hear similar variants, depending on emphasis. For example, a speaker might slightly rearrange parts in conversation, but the basic relationships should stay clear:

• tumia bisibisi = the tool being used
• kukaza = the purpose
• skrubu za kiti hiki = what is being tightened

For learners, the original sentence is a very good model to copy.