Weak Roots: the Secret of Irregular Verbs
קָנִיתִי and not קָנָתִי, אֶסַּע and not אֶנְסַע, לָשֶׁבֶת and not לִישֹׁב. It is not chaos: four families, and one rule for each.
Some letters are “weak” (ה, ו, י, נ): they disappear or change. Know where the weak letter sits in the root, and you know how the verb will behave.
פ, ע, ל: how the families are named
Weak letters
Most roots behave like כ־ת־ב: three strong letters that stay in every form. But some letters do not hold up: ה at the end of the root, ו or י in the middle, נ or י at the start. They get swallowed, swapped or dropped.
A “family” (גִּזְרָה) is a group of roots with a weak letter in the same place. Every family changes in the same way, so if you understand one verb in a family, you understand dozens.
The verbs the past-tense lesson called “irregular” (קָנִיתִי, קַמְתִּי, הָיִיתִי) are exactly these. Here you find the rule behind them.
The names of the slots in a root
Grammarians name the letters of a root after the word פָּעַל. ל״ה (lamed-he) means the third letter (in the ל slot) is ה. פ״נ (pe-nun) means the first letter (in the פ slot) is נ.
The four families in this lesson
| Family | Where the weak letter is | Roots | Infinitives |
|---|---|---|---|
| ל״ה | third letter ה | ק־נ־ה · ר־א־ה · ע־שׂ־ה | לִקְנוֹת · לִרְאוֹת · לַעֲשׂוֹת |
| ע״ו / ע״י | second letter ו or י | ק־ו־ם · ג־ו־ר · שׁ־י־ר | לָקוּם · לָגוּר · לָשִׁיר |
| פ״נ | first letter נ | נ־פ־ל · נ־ס־ע · נ־ת־ן | לִפֹּל · לִנְסֹעַ · לָתֵת |
| פ״י | first letter י | י־שׁ־ב · י־ר־ד · י־צ־א | לָשֶׁבֶת · לָרֶדֶת · לָצֵאת |
ל״ה: the ה that changes costumesthe big family
The final ה is not really a letter
In ק־נ־ה, ר־א־ה, ע־שׂ־ה, שׁ־ת־ה and ה־י־ה the final ה is not pronounced. It only marks a vowel. So when something is added, it changes: to י before a past ending (קָנִיתִי), to ת in the “she” form (קָנְתָה), to וֹת in the infinitive (לִקְנוֹת).
Before an ending that starts with a vowel, it simply disappears: קָנוּ, קוֹנִים, יִקְנוּ.
The easiest clue: an infinitive ending in ־וֹת is almost always ל״ה. לִרְאוֹת, לִשְׁתּוֹת, לַעֲשׂוֹת, לִהְיוֹת.
What happens to the ה of ק־נ־ה
| Form | Example | What happened to the ה |
|---|---|---|
| Infinitive | לִקְנוֹת | becomes ־וֹת |
| Past, I | קָנִיתִי | becomes י before the ending |
| Past, she | קָנְתָה | becomes ת |
| Past, they | קָנוּ | disappears |
| Present | קוֹנֶה · קוֹנָה · קוֹנִים | ה in the masculine, disappears in the plural |
| Future | אֶקְנֶה · יִקְנוּ | ה at the end, disappears before ־וּ |
| Imperative | קְנֵה · קְנִי | tsere in the masculine, disappears before ־ִי |
It works in every binyan
In every binyan, a ל״ה verb ends in ה in the past (“he”) and in ־וֹת in the infinitive.
לְהִתְרָאוֹת is a verb!
לְהִתְרָאוֹת is ר־א־ה in the הִתְפַּעֵל binyan, meaning “to see each other”. When you say goodbye with לְהִתְרָאוֹת, you are really saying “(may we get) to see each other again”.
Quick check
Yesterday I bought bread. Pick the past form for “I”.
אֶתְמוֹל ___ לֶחֶם.
ע״ו / ע״י: the root with only two letters
The middle letter is a vowel
In ק־ו־ם, ג־ו־ר, ר־ו־ץ the ו in the middle is really the vowel “u”. When the verb is conjugated, it disappears and only two letters remain: קַמְתִּי, קָם, קָמָה.
In the infinitive and the future it comes back: לָקוּם, אָקוּם, יָקוּם. In ע״י roots (שׁ־י־ר, שׂ־י־ם) the י comes back: לָשִׁיר, אָשִׁיר.
In these roots, “he” in the past and “he” in the present are the same word: קָם. קָמָה is also written the same; the only difference is the stress: in the past KAma (on the first syllable), in the present kaMA (on the last).
ק־ו־ם in three tenses
| Tense | אֲנִי | הוּא | הִיא | הֵם |
|---|---|---|---|---|
| Past | קַמְתִּי | קָם | קָמָה | קָמוּ |
| Present | קָם / קָמָה | קָם | קָמָה | קָמִים |
| Future | אָקוּם | יָקוּם | תָּקוּם | יָקוּמוּ |
Infinitive: לָקוּם. Imperative: קוּם, קוּמִי, קוּמוּ.
Three more from the same family
sing: he sang / sings, to sing, I will sing
put: he put / puts, to put, I will put
come: he came / comes, to come, I will come
Quick check
Yesterday I got up early. Pick the past form for “I”.
אֶתְמוֹל ___ מֻקְדָּם.
פ״נ: the נ that gets swallowed
נ + consonant = dagesh
When the נ at the start of the root would come with no vowel (with a shva) before another letter, it is swallowed by the next letter and leaves a dagesh there. Instead of אֶנְסַע you say אֶסַּע, and instead of יִנְפֹּל you say יִפֹּל.
In the past the נ stays, because it has a vowel: נָסַע, נָפַלְתִּי, נָתַנּוּ. It disappears in the future, in the imperative and sometimes in the infinitive.
ל־ק־ח behaves exactly like פ״נ, even though it starts with ל: אֶקַּח, קַח, לָקַחַת.
How the נ is swallowed
Five useful verbs
| Meaning | Past (he) | Future (I) | Infinitive | Imperative |
|---|---|---|---|---|
| to travel | נָסַע | אֶסַּע | לִנְסֹעַ | סַע |
| to touch | נָגַע | אֶגַּע | לָגַעַת | גַּע |
| to give | נָתַן | אֶתֵּן | לָתֵת | תֵּן |
| to fall | נָפַל | אֶפֹּל | לִפֹּל | — |
| to take | לָקַח | אֶקַּח | לָקַחַת | קַח |
לָתֵת is the most extreme: both the first נ and the last נ disappear. Only ת is left.
In הִפְעִיל the נ always disappears
to say, to tell
to know (someone), to be acquainted with
to save, to rescue
to look, to gaze
This is why לְהַגִּיד looks strange: the root is נ־ג־ד (as in נֶגֶד, facing, against). הִנְגִּיד became הִגִּיד.
Quick check
Tomorrow I will travel to Tel Aviv. Pick the future form for “I”.
מָחָר ___ לְתֵל אָבִיב.
פ״י: the י that vanishes in the future
Tsere in the future, ־ֶת in the infinitive
In roots like י־שׁ־ב, י־ר־ד, י־צ־א, י־ד־ע the י stays in the past (יָשַׁבְתִּי) and disappears in the future. In its place you get an “e” vowel (tsere): אֵשֵׁב, תֵּשֵׁב, יֵרֵד.
The infinitive loses the י too and gets a ת at the end: לָשֶׁבֶת, לָרֶדֶת, לָצֵאת, לָדַעַת. In הִפְעִיל the י becomes וֹ: הוֹשִׁיב, הוֹרִיד, הוֹצִיא.
הָלַךְ behaves like פ״י, even though it starts with ה: אֵלֵךְ, לָלֶכֶת, לֵךְ. That is why it sounds “irregular”.
Five verbs, all the forms
| Meaning | Past (he) | Future (I) | Infinitive | Imperative | הִפְעִיל |
|---|---|---|---|---|---|
| to sit | יָשַׁב | אֵשֵׁב | לָשֶׁבֶת | שֵׁב | הוֹשִׁיב |
| to go down, to get off | יָרַד | אֵרֵד | לָרֶדֶת | רֵד | הוֹרִיד |
| to go out, to leave | יָצָא | אֵצֵא | לָצֵאת | צֵא | הוֹצִיא |
| to know | יָדַע | אֵדַע | לָדַעַת | דַּע | הוֹדִיעַ |
| to go, to walk | הָלַךְ | אֵלֵךְ | לָלֶכֶת | לֵךְ | הוֹלִיךְ |
The הִפְעִיל column shows the וֹ: לְהוֹרִיד (to take something down), לְהוֹצִיא (to take something out).
Where does the “exit” sign come from?
Nouns keep the root too: יְצִיאָה (exit, י־צ־א), יְרִידָה (descent, י־ר־ד), יְשִׁיבָה (meeting, yeshiva, י־שׁ־ב), מוֹצָא (origin, הִפְעִיל). The sign יְצִיאָה and the verb לָצֵאת share one root.
Quick check
How do you say “I will get off (at the next stop)”?
___ בַּתַּחֲנָה הַבָּאָה.
Root detectivereview it all
How to spot the family from a strange form
Came across a form that does not fit three letters? Look for the clue. Every family leaves a fixed “fingerprint”, and if you recognise it you can rebuild the root and look it up in the dictionary.
A verb can belong to two families at once: יָצָא is both פ״י and ל״א, and נָשָׂא is both פ״נ and ל״א.
The fingerprints
| Clue | Family | Example |
|---|---|---|
| infinitive in ־וֹת, or ־ִיתִי in the past | ל״ה | לִקְנוֹת · קָנִיתִי |
| only two letters, with וּ or ִי in the middle | ע״ו / ע״י | קַמְתִּי · לָשִׁיר |
| a strong dagesh where a letter is missing | פ״נ | אֶסַּע · אֶתֵּן |
| tsere in the future, ־ֶת in the infinitive, הוֹ־ in הִפְעִיל | פ״י | אֵשֵׁב · לָשֶׁבֶת · הוֹרִיד |
What is the root?
A future form. What is the root?
תֵּצְאִי
And there are more families
There are other families too: ל״א (קָרָאתִי, מָצָאתִי, where the א is silent), ע״ע, where the last two letters are identical (סָבַב, סוֹבֵב), and roots with guttural letters (א, ה, ח, ע, ר) that do not take a dagesh and change the vowels. The rule stays the same: spot the problem letter, and it explains the form.
Common mistakes
- קָנָתִיקָנִיתִי
ל״ה: before a past ending the ה becomes י.
- אֲנִי אֶנְסַעאֲנִי אֶסַּע
פ״נ: the נ is swallowed in the future and leaves a dagesh.
- קוּמְתִּיקַמְתִּי
ע״ו: in the past the ו disappears completely, and the vowel is “a”.
- אֲנִי אֶיְשַׁבאֲנִי אֵשֵׁב
פ״י: the י disappears in the future and the vowel is tsere.
What to remember
- The family’s name says where the weak letter is: פ = first, ע = second, ל = third.
- ל״ה: ־ִיתִי in the past, ־וֹת in the infinitive (קָנִיתִי, לִקְנוֹת).
- ע״ו: two letters in the past, וּ or ִי in the future (קַמְתִּי, אָקוּם).
- פ״נ: the נ is swallowed and leaves a dagesh (אֶסַּע, תֵּן).
- פ״י: tsere in the future, ־ֶת in the infinitive, הוֹ־ in הִפְעִיל (אֵשֵׁב, לָשֶׁבֶת, הוֹשִׁיב).
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Frequently asked questions
- Do I have to memorise all the families?
- Not all of them. The four families in this lesson cover most of the “irregular” verbs you will hear day to day. It is enough to remember one verb from each family (קָנָה, קָם, נָסַע, יָשַׁב) and compare every new verb to it.
- What is the difference between ע״ו and ע״י?
- Only the vowel that comes back in the infinitive and the future: ע״ו takes וּ (לָקוּם, אָקוּם) and ע״י takes ִי (לָשִׁיר, אָשִׁיר). In the past they are identical: קַמְתִּי, שַׁרְתִּי.
- Why is לָתֵת so short?
- Because the root נ־ת־ן loses both its נ’s: the first is swallowed as in every פ״נ verb, and the last is swallowed into the ת of the infinitive. What is left is לָתֵת. In the past both come back: נָתַן.
- How do I look up a verb like this in the dictionary?
- Rebuild the root from the clues (see the fingerprints table) and look up the “he” past form: אֶסַּע → נ־ס־ע → נָסַע. Online dictionaries also let you type the form itself, but understanding the root is what builds intuition.
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