يخيط الخياط القماش.

Arabic often uses verb–subject–object order as a very normal, neutral sentence pattern, especially in Modern Standard Arabic.

So:

• يخيط الخياط القماش = sews the tailor the cloth/fabric
• Natural English order is still The tailor sews the cloth/fabric

Arabic can also say:

• الخياط يخيط القماش

That is also correct, but it starts with the subject instead of the verb.

يخيط is in the imperfect form. In this sentence, it can mean:

• sews
• is sewing

Arabic imperfect verbs often cover both the simple present and the present progressive. The exact meaning depends on context.

So يخيط does not by itself force a difference between sews and is sewing.

In the Arabic imperfect, the first letter often shows the person.

Here, يـ marks third person masculine singular:

• يخيط = he sews / he is sewing

That matches الخياط, which is a singular masculine noun.

They come from the same root: خ ي ط.

This root is connected with sewing and thread.

• يخيط = he sews
• الخياط = the tailor

So the words are related in meaning, just as English has related words like to sew and sewing or tailor-made.

Also, the fully vocalized form of الخياط is usually الخيّاط. The doubled ي sound is shown by the shadda.

With full vowel endings, the sentence is:

يَخِيطُ الخَيَّاطُ القُمَاشَ

The endings show the grammar:

• يخيطُ — the verb, here in the indicative
• الخياطُ — the subject, so it is nominative
• القماشَ — the direct object, so it is accusative

In normal Arabic writing, these short vowels are usually omitted, so you often see only:

يخيط الخياط القماش

الـ is the Arabic definite article, equivalent to the.

So:

• الخياط = the tailor
• القماش = the cloth / the fabric

Arabic uses the definite article in some places where English may or may not use the, depending on style and context. So sometimes the most natural English translation may sound a little less definite than the Arabic form.

Also, because these nouns are definite, they do not take tanwīn.

A careful full pronunciation is:

yakhīṭu al-khayyāṭu al-qumāsha

A few useful sound notes:

• خ = a throaty kh sound, like the ch in German Bach or Scottish loch
• ق = q, a deeper sound than English k
• الخياط is pronounced al-khayyāṭ, with a doubled y sound

In pause, final short vowels are often not pronounced, so you may hear something closer to:

yakhīṭ al-khayyāṭ al-qumāsh

Yes. That is also grammatical.

Compare:

• يخيط الخياط القماش — verb-first, a very standard MSA pattern
• الخياط يخيط القماش — subject-first, often used for emphasis or a different flow

Both mean essentially the same thing here.

Arabic often builds that information into the verb itself.

In يخيط:

• the يـ already tells you it is he
• the imperfect form can already mean sews / is sewing

So Arabic does not need a separate word for he or is in this sentence.

That is why a single Arabic word can correspond to more than one English word.

Arabic has no separate indefinite article equivalent to English a/an.

So:

• خياط would mean a tailor or just tailor, depending on context
• الخياط means the tailor

In your sentence, the nouns are definite because they have الـ. If the sentence were made indefinite, the form would change accordingly.