The l/o alternation
In short
| o-form | l-forms | |
|---|---|---|
| participle | video, pao, rekao | videla, videli |
| noun | deo, ugao, sto, posao | dela, ugla, stola; delovi |
| adjective | topao, okrugao, beo, ceo | topla, okrugli, beli |
| loanword | — | kabl, metal, hotel, bicikl |
l closing a syllable → o; l before a vowel stays. Loanwords keep l everywhere.
B2 · Lesson 2 · Prelaz l u o
The full explanation, from the lesson that teaches this rule
You have been using this rule since your first past tense. A man says video sam, a woman says videla sam, a group says videli smo. Why video and not videl? Because in these words Serbian does not let an l stand at the end of a syllable. Where it would, it turns into o.
Look at the three forms side by side. In vi-de-la and vi-de-li the l is followed by a vowel, so it opens a new syllable and survives. In the masculine form there is no ending at all, the l would close the word, and so it becomes o: video. This change is called the l/o alternation.
1. The masculine past participle
| Verb | Man (-o) | Woman (-la) | Group (-li) |
|---|---|---|---|
| videti | video | videla | videli |
| pasti | pao | pala | pali |
| reći | rekao | rekla | rekli |
| doneti | doneo | donela | doneli |
| čuti | čuo | čula | čuli |
In rekao and došao the stem ends in a consonant (rek-, doš-), so a fleeting a appears before the o: rek-a-o. It is the same fleeting a you already know from ugao/ugla below.
2. Nouns: the dictionary form hides the stem
The same thing happens in a group of masculine nouns. The nominative singular has no ending, so the stem-final l becomes o. Every other case adds a vowel, and the l comes back. The practical consequence: the form you meet in a sentence (bez tog dela) and the form in the dictionary (deo) do not look alike.
| Nominative sg (dictionary) | Genitive sg | Other singular | Nominative pl |
|---|---|---|---|
| deo (part) | dela | delu, delom | delovi |
| ugao (corner) | ugla | uglu, uglom | uglovi |
| sto (table) | stola | stolu, stolom | stolovi |
| posao (job, work) | posla | poslu, poslom | poslovi |
| pepeo (ash) | pepela | pepelu | — |
- sto is stol with the l turned into o, and the two o's merged into one.
- ugao and posao also show the fleeting a: the stems are ugl- and posl-.
3. Adjectives: the short masculine form
Adjectives whose stem ends in l show o in exactly one place: the short (indefinite) masculine singular, the form used after je and in the dictionary. Every other form has an ending and keeps the l, including the long form okrugli.
| Masculine (short) | Feminine | Neuter | Masculine plural |
|---|---|---|---|
| topao (warm) | topla | toplo | topli |
| okrugao (round) | okrugla | okruglo | okrugli |
| beo (white) | bela | belo | beli |
| debeo (thick) | debela | debelo | debeli |
| ceo (whole) | cela | celo | celi |
4. The plural keeps the l
Every plural form has an ending that begins with a vowel, so in the plural the l is always back: delovi, uglovi, stolovi for nouns, beli, topli for adjectives, pali, rekli for participles. If you see an o-form, you are looking at a singular.
5. Loanwords keep their l
The rule is old. Words that came into Serbian after it stopped working keep a final l in every form: kabl, metal, hotel, bicikl, model, materijal, ventil. Their paradigm is regular: kabl, kabla, kablovi. You do not need a list: if a word looks international, expect it to keep its l.
Looking a word up
- You meet a form with l before a vowel: dela, ugla, topla.
- Strip the ending to get the stem: del-, ugl-, topl-.
- Turn the final l into o (adding a fleeting a between two consonants): deo, ugao, topao. That is the dictionary form.
- If the word looks international (kabla, metala), leave the l alone: kabl, metal.
Do not write videl, topal or del: the masculine forms of these words never end in l. And do not do the opposite with loanwords: kabl is right, kabao is a different word (a bucket).
Check what you read
6 of the 15 questions this lesson asks in the app. Type the form or pick the answer.
Telefon mi je(pasti) na pod.
Petar je(reći) da će popraviti lampu.
Marko je ___ novi sto.
Bez ovog(deo) mašina ne radi.
You read "pored stola". Which form do you look up in the dictionary?
Ovaj zid je ___.
Examples from the course
The marked word is where the rule applies. Press play to hear the sentence.
Uglovi ovog ekrana su okrugli.
The corners of this screen are rounded.
Ceo mehanizam je napravljen od metala.
The whole mechanism is made of metal.
Svi delovi su pali na pod.
All the parts fell on the floor.
Beli vijci su ispali iz kutije.
The white screws fell out of the box.
Pepeo je pao na beli stolnjak.
The ash fell on the white tablecloth.
Gde si našao deo za ovu fioku?
Where did you find a part for this drawer?
Polica stoji u uglu, iznad radnog stola.
The shelf is in the corner, above the desk.
Doneo sam alat, ali sam zaboravio odvijač.
I brought the tools, but I forgot the screwdriver.
Majstori su došli i zamenili ventil na slavini.
The repairmen came and replaced the valve on the tap.
Ugao ovog stola je oštar, pazi na koleno.
The corner of this table is sharp, mind your knee.
Sentences in the course that use this rule: 195
Try it yourself
Translate a sentence that uses this rule. The check marks the word that went wrong and names the rule behind it, as in the app.
Sentences
Write it in Serbian
The corners of this screen are rounded.