In short

Arabic points with two families of words: a near one built on هٰذا “this”, and a far one built on ذٰلِكَ “that”. Each family has a masculine and a feminine form, a dual, and a plural, and you choose between them the same way you chose an adjective in lesson 8 - by looking at the thing you are pointing at. The good news is that these words barely inflect: apart from the duals, every demonstrative in the language is مَبْنِيّ, frozen in one shape whatever the sentence does to it.

The whole lesson then turns on one very small thing: whether the noun after the demonstrative wears الـ. هٰذا كِتابٌ is already a complete sentence - “this is a book”. هٰذا الكِتابُ is not a sentence at all; it is the two-word phrase “this book”, still waiting for someone to say something about it. One article is the difference between making a statement and merely naming an object, and beginners get it wrong constantly. Fix the pair now and everything else in this lesson is bookkeeping.

The rule

1. The near series. These point at what is close - in space, in time, or simply on the page in front of you: هٰذا (m.sg.)، هٰذِهِ (f.sg.)، هٰذانِ / هٰذَيْنِ (m.du.)، هاتانِ / هاتَيْنِ (f.du.)، هٰؤُلاءِ (plural, people). Inside them you can still see the joints: ها is the old particle of drawing attention, and ذا، ذِهِ، ذانِ، تانِ are the pointing words proper. That is why the feminine dual is هاتانِ and not *هٰذَتانِ - it is ها + تانِ.

2. The far series. These point at what is further away, or - very often in modern prose - back at something already mentioned: ذٰلِكَ (m.sg.)، تِلْكَ (f.sg.)، أُولٰئِكَ (plural, people). Here too the parts are visible: ذا + لِ + كَ. The ل is the marker of distance, and the final كَ is addressed to the person you are speaking to, roughly “that one over there, as you can see”. Modern writing keeps ذٰلِكَ fixed for every listener; only old and very formal texts vary that final letter.

3. Everything but the duals is frozen. A demonstrative is مَبْنِيّ - it does not take case endings at all. هٰذا is هٰذا as subject, after a preposition, everywhere; هٰؤُلاءِ always ends in a kasra; ذٰلِكَ always ends in a fatḥa; تِلْكَ never changes. Only the dual forms behave like real duals and show the alif / yāʾ alternation you met in lesson 12:

• هٰذانِ الوَلَدانِ صَديقانِ. - nominative, so the alif form
• أَنا مَعَ هٰذَيْنِ الوَلَدَيْنِ. - after a preposition, so the yāʾ form
• هاتانِ الغُرْفَتانِ نَظيفَتانِ. / فِي هاتَيْنِ الغُرْفَتَيْنِ

Notice that the demonstrative and the noun move together: both are nominative, or both oblique. They are one unit, so they cannot disagree.

4. هٰذا كِتابٌ - the sentence. Put a demonstrative in front of an indefinite noun and you have a complete nominal sentence of the kind you built in lesson 2. The demonstrative is the مُبْتَدَأ, the indefinite noun is the خَبَر, and English has to supply a verb that Arabic does not need:

• هٰذا بَيْتٌ. - This is a house.
• هٰذِهِ سَيّارَةٌ سَريعَةٌ. - This is a fast car.
• ذٰلِكَ مُهَنْدِسٌ. - That is an engineer.
• هٰؤُلاءِ طُلّابٌ. - These are students.

The tanwīn on the second word is doing real work: it marks that noun as indefinite, and an indefinite noun after the pointer can only be the predicate - the sentence is finished.

5. هٰذا الكِتابُ - the phrase. Put the same demonstrative in front of a noun that carries الـ and nothing has been stated yet. The two words simply stand side by side as one naming expression, “this book”, and the sentence is still to come:

• هٰذا البَيْتُ - this house
• هٰذِهِ السَّيّارَةُ - this car
• تِلْكَ المَدينَةُ - that city
• هٰؤُلاءِ الطُّلّابُ - these students

The reason is worth keeping, because it explains every case in this lesson: a demonstrative is definite by nature. Definite pointer + definite noun = one referring phrase. Definite pointer + indefinite noun = subject + predicate = a sentence. Definiteness decides, not intonation.

6. Both constructions at once. Once you have the phrase, you can say something about it - and what you add is, of course, indefinite:

• هٰذا البَيْتُ كَبيرٌ. - This house is big.
• هٰذِهِ السَّيّارَةُ قَديمَةٌ. - This car is old.
• هٰؤُلاءِ الطُّلّابُ مِنْ مِصْرَ. - These students are from Egypt.

And if you want an adjective inside the phrase rather than a predicate after it, the adjective agrees in definiteness and takes الـ as well (lesson 8): هٰذا البَيْتُ الكَبيرُ “this big house”, which can then get its own predicate - هٰذا البَيْتُ الكَبيرُ قَديمٌ “this big house is old”. Three words, one article missing or present, three different meanings; read the pair aloud until the difference is audible.

7. Non-human plurals point with هٰذِهِ. This is lesson 11 turning up again, and it is the second big trap. Anything that is not a person - books, cars, houses, ideas - is treated in the plural as a feminine singular, so it takes the feminine singular demonstrative:

• هٰذِهِ الكُتُبُ جَديدَةٌ. - These books are new.
• تِلْكَ السَّيّاراتُ غالِيَةٌ. - Those cars are expensive.
• هٰذِهِ مُدُنٌ كَبيرَةٌ. - These are big cities.

هٰؤُلاءِ and أُولٰئِكَ are for people only: هٰؤُلاءِ الأَوْلادُ، أُولٰئِكَ المُعَلِّماتُ، هٰؤُلاءِ المُهَنْدِسونَ. Writing *هٰؤُلاءِ الكُتُبُ is the kind of mistake a native speaker notices instantly, and it is entirely avoidable: ask yourself “are these human?” before you reach for the plural demonstrative.

8. An already-definite noun still gives you a sentence. A noun made definite by an attached pronoun (lesson 7) cannot take الـ - one definiteness marker per word. So when such a noun follows a demonstrative, the phrase reading is simply not available, and what you get is the sentence:

• هٰذا كِتابي. - This is my book. (never “this book of mine”)
• هٰذِهِ مَدْرَسَتُنا. - This is our school.
• هٰذا أَحْمَدُ. - This is Ahmad.

To say “this book of mine”, you flip the order and put the demonstrative after the noun: كِتابي هٰذا جَديدٌ “this book of mine is new”، سَيّارَتُها تِلْكَ “that car of hers”. The same flip is what you will use with the إِضافَة in lesson 20. With an الـ noun, though, keep the normal order - هٰذا البَيْتُ, not البَيْتُ هٰذا.

9. The noun carries the visible grammar. Because the demonstrative is frozen, the case of the phrase shows up on the noun alone:

• هٰذا الكِتابُ جَديدٌ. - nominative on الكِتابُ
• المِفْتاحُ فِي هٰذِهِ الحَقيبَةِ. - genitive after the preposition, on الحَقيبَةِ
• مَعَ هٰؤُلاءِ الطُّلّابِ - genitive again, while هٰؤُلاءِ keeps its own kasra

The duals are the exception, as in point 3: there both words move. Everything else you write once and forget.

10. The dagger alif. هٰذا، هٰذِهِ، هٰؤُلاءِ، ذٰلِكَ، أُولٰئِكَ all contain a long ā that is pronounced but not written as an alif. In fully vocalized text it appears as a small vertical stroke, the أَلِف خَنْجَرِيَّة (dagger alif), and this path prints it. In ordinary Arabic you will see هذا، هذه، هؤلاء، ذلك، أولئك with no mark at all - the vowel is still there in the pronunciation. Never “help” the spelling by writing a full alif: *هاذا and *ذالك are wrong. Two more oddities in the same family: أُولٰئِكَ contains a silent و that is written and never pronounced, and هٰذِهِ ends in a real ه, not a ة.

11. Left to other lessons. “This is the book which I read” needs الَّذي - lesson 39. “There is a book here / over there” with هُنا and هُناكَ belongs to lesson 17. Both are neighbours of this topic, and neither is needed to point at something.

Forms & patterns

The near series, in full. The right-hand column shows the shape you will actually write.

The far series, exactly parallel:

The four far duals are printed for completeness only. They are genuinely rare in modern writing - recognize them if you meet them and do not spend memory on producing them. The three you must own are ذٰلِكَ، تِلْكَ، أُولٰئِكَ.

The two constructions, side by side. This is the table to memorize:

Frozen singular against declining dual - watch which words change:

The accusative of the dual uses the same هٰذَيْنِ / هاتَيْنِ forms as the genitive; you will start writing it in lesson 29, once verbs have objects.

Spelling: what this path prints, and what you will see everywhere else.

Examples

Common mistakes

• هٰذا كِتابٌ (meaning “this book”) -> هٰذا الكِتابُ - with an indefinite noun you have written the whole sentence “this is a book”. The phrase needs الـ on the noun.
• هٰذا الكِتابُ (meaning “this is a book”) -> هٰذا كِتابٌ - the reverse error. With الـ nothing has been said yet; you have only named the object.
• هٰذا البَيْتُ الكَبيرُ (meaning “this house is big”) -> هٰذا البَيْتُ كَبيرٌ - a predicate is indefinite. Put الـ on the adjective and it joins the phrase instead.
• هٰؤُلاءِ الكُتُبُ -> هٰذِهِ الكُتُبُ - هٰؤُلاءِ is for people. Non-human plurals take the feminine singular, exactly as in lesson 11.
• أُولٰئِكَ المُدُنُ -> تِلْكَ المُدُنُ - same rule in the far series: cities are not people.
• هٰذِهِ الكِتابُ -> هٰذا الكِتابُ - كِتاب is masculine, so the pointer is masculine. Check the noun’s gender before you point.
• هٰذا كِتابي (meaning “this book of mine”) -> كِتابي هٰذا - a noun carrying a pronoun suffix cannot take الـ, so the demonstrative has to follow it to make a phrase.
• فِي هٰذانِ الكِتابَيْنِ -> فِي هٰذَيْنِ الكِتابَيْنِ - the dual demonstrative is the one form that declines, and after a preposition it must match its noun.
• هٰذَيْنِ الطّالِبانِ نَشيطانِ -> هٰذانِ الطّالِبانِ نَشيطانِ - subject position, so both words take the alif form.
• هاذا / ذالك -> هٰذا / ذٰلِكَ (written هذا / ذلك) - the long ā of these words is never written as a full alif.
• أُلٰئِكَ -> أُولٰئِكَ - the silent و is part of the spelling even though you do not pronounce it.

Tips

• One question decides everything: does the noun after the demonstrative wear الـ? With الـ it is a phrase; without it, you have made a statement. Say هٰذا بَيْتٌ / هٰذا البَيْتُ out loud as a pair until the choice is reflex.
• Learn هٰذا and هٰذِهِ first and thoroughly. هٰذِهِ alone covers feminine singulars and every non-human plural in the language, which makes it the most useful of them all.
• Remember that ال after a demonstrative is هَمْزَةُ الوَصْل: هٰذا الكِتابُ runs together as one unbroken group, with no glottal stop and no extra vowel between the two words.
• Keep writing the shadda on sun letters inside the phrase: هٰذا الطّالِبُ، هٰذِهِ السَّيّارَةُ، ذٰلِكَ الرَّجُلُ.
• Hook the far series on its own shape: ذا + لِ + كَ. The ل of distance shows up only in ذٰلِكَ and تِلْكَ, but every far form ends in that كَ.
• Do not practise producing the far duals ذانِكَ، تانِكَ. Recognizing them is enough; even careful modern writers reach for something else.
• Print the dagger alif while you are learning, then drop it when you write real Arabic - but never drop the sound. هذا is two syllables with a long first one.
• Pointing at a person you can see, and pointing back at something said three lines earlier, use the same words. In news and academic prose ذٰلِكَ is usually the second kind, and it is one of the commonest words on the page.