Esperanto word building: roots, affixes, compounds

Esperanto words are built from parts that never change shape: a root, optional prefixes and suffixes, and a grammatical ending. Mal·san·ul·ej·o is "opposite + healthy + person + place + noun", which means "hospital". Once you know the parts, you can take a word apart – and build new ones.

malprefixopposite

sanroothealthy

ulsuffixperson

ejsuffixplace

oendingnoun

malsanulejohospital

This is why Esperanto needs fewer roots than other languages. Zamenhof's first textbook, the Unua Libro (1887), had only 917 roots. With endings, affixes and compounding, each root produces a family of related words.

san-healthlern-to learnparol-to speak, to talklabor-job, workvid-to seeskrib-to writebon-goodam-to love

malsanulejo

hospital

1. malprefixopposite
2. sanroothealth
3. ulsuffixperson
4. ejsuffixplace
5. oendingnoun

In the dictionary →

Point at or tap a word to see how it is built and what it means.

Word families: Reta Vortaro (GPL); structure: Esperantopedia's analyser; meanings: Esperantopedia, Wiktionary, ReVo.

lernrootlearn

ejsuffixplace

estrsuffixleader, head

oendingnoun

lernejestrohead teacher

reprefixagain, back

sanroothealthy

iĝsuffixbecome, get

iendinginfinitive

resaniĝito recover

geprefixboth sexes

patrrootfather

oendingnoun

jendingplural

gepatrojparents

Choose a root, then add a prefix, suffixes and an ending: the word and its meaning change as you go.

lernlearnejplaceestrleader, headonoun

= lernejestrohead teacher

Examples lernejestro resaniĝi gepatroj

prefix

nonemal- oppositere- againek- startdis- apartge- both sexesĉef- chiefmis- wronglypra- ancienteks- formerbo- in-law

root

lern- learnsan- healthybel- beautifulpatr- fatherdom- house

suffixes (up to 2)

-ul- person-in- female-ist- professional-ej- place-il- tool-ar- group-aĵ- concrete thing-ec- quality-ad- continued action-ig- make-iĝ- become-et- small-eg- big-ebl- possible to-id- offspring-an- member-estr- leader-uj- container-er- smallest unit-ism- doctrine-aĉ- bad quality-ind- worthy of-em- tendency

ending

-o noun-a adjective-e adverb-i infinitive-as present tense-is past tense-os future tense-us conditional-u volitive-oj noun · plural-on noun · accusative-ojn noun · plural · accusative

#Four kinds of building blocks

The Academy's dictionary (Akademia Vortaro) counts 4,953 official elements. That figure includes the 11 endings and 184 small words; the rest need an ending. The 10th Official Addition of 2023 added 420 new roots.

#Endings decide the word class

The same root becomes a noun, adjective, adverb or verb just by changing the ending. See nouns and adjectives and verbs.

Each root has a basic meaning of its own: an action, a quality or a thing. The -o form shows it (PMEG). Kombi "to comb" is an action, so the comb is kombilo "combing tool". Broso "brush" is a thing, so brushing is simply brosi.

#Affixes add meaning

Prefixes come before the root, suffixes after it. Each adds one meaning: mal- "opposite", -ej- "place", -ul- "person", -in- "female", -et- "small", -eg- "big", -ig- "make", -iĝ- "become".

Affixes are also ordinary roots. Ejo means "place", ilo "tool", eta "tiny", ege "very", ree "again".

#A word family: lern- "learn"

A second family, from san- "healthy": sana "healthy", malsana "ill", malsano "illness", malsanulo "patient", malsanulejo "hospital", sanigi "to heal", resaniĝi "to recover".

#Compounds: the main word comes last

Rule 11 of the Fundamento: compounds are made by joining roots, with the main word last. The front part narrows the meaning of the last part (PMEG).

• vaporŝipo – "steamship" (a ship driven by steam); ŝipvaporo would be steam from a ship
• fervojo – "railway" (literally "iron road")
• ĉefurbo – "capital city" (main town)
• dikfingro – "thumb" (thick finger)

A linking vowel, usually -o-, can go between the parts for easier pronunciation or clarity: lern·o·libr·o, sang·o·ruĝ·a "blood-red". It is usually left out when the front part simply describes the head like an adjective: dikfingro, not dikafingro (PMEG).

A phrase with a preposition can also become one word. Here the main word is not last: sen hejmo "without a home" → senhejma "homeless"; inter nacioj → internacia "international"; sub tegmento → subtegmento "attic". See prepositions.

#From 917 roots to tens of thousands of words

The Unua Libro of 1887 had 917 roots, and Zamenhof's Universala Vortaro (1894) added 1,740 more. The largest dictionary, the Plena Ilustrita Vortaro, listed 16,780 entries and 46,890 lexical units in its 2002 edition. Most of these units are derived words and compounds built from a much smaller set of roots.

The Academy recommends the principle of necessity and sufficiency, formulated by René de Saussure in 1913. Use every part needed for a clear meaning, and no more. Sufiĉo already means "sufficiency", so sufiĉeco adds nothing.

#Traps

1. Fixed meanings. The parts explain a word but do not define it. Lernejo is a school, not any place where someone learns. Other examples: vortaro "dictionary" (collection of words), arbaro "forest", vagonaro "train", pordego "gate", rideti "to smile", ŝtrumpeto "sock". PMEG notes that ladskatolo is a tin can, not any tin box.

2. Words that only look built. Kolego "colleague" is not kol·eg·o "huge neck". Okulo "eye" is not ok·ul·o "eight-person", and haringo "herring" is not har·ing·o. PMEG counts more than 150 roots in PIV that merely look as if they contain the suffix -et-.

3. -ig- and -iĝ- depend on the root. Fermi "to close (something)" gives fermiĝi "to close (by itself)". Sidi "to sit" gives sidigi "to seat someone" and sidiĝi "to sit down". Check in a dictionary whether a verb takes an object.

4. -um- has no fixed meaning. Kolumo "collar", aerumi "to air out" and plenumi "to fulfil" must be learned one by one.

#Examples in sentences

• Mia fratino lernas en granda lernejo. – "My sister studies at a big school."
• La lernantoj demandis la instruiston pri la lernolibro. – "The pupils asked the teacher about the textbook."
• Esperanto estas facile lernebla lingvo. – "Esperanto is an easy language to learn."
• Mia avo laboris kiel fervojisto. – "My grandfather worked as a railwayman."
• Mia dormoĉambro estas malgranda sed hela. – "My bedroom is small but bright."
• La vortaro helpas min kompreni novajn vortojn. – "The dictionary helps me understand new words."
• Ĉu vi havas tranĉilon por la pano? – "Do you have a knife for the bread?"
• Ŝia parolado estis mallonga kaj klara. – "Her speech was short and clear."
• Vespere ni hejmeniris piede. – "In the evening we walked home."

#Common questions

#How many words does Esperanto have?

There is no fixed number, because new words can be built at any time. The largest dictionary, PIV (2002), has 46,890 lexical units; the Academy's official list has 4,953 elements plus 420 roots added in 2023.

#Can I make up new words in Esperanto?

Yes. Any correct combination of parts is grammatical and usually understood. Check a dictionary first, because an established word may already exist with a fixed meaning.

#Why is the main word last in Esperanto compounds?

Rule 11 of the Fundamento puts the main word at the end. The front part only narrows it: vaporŝipo is a kind of ship, not a kind of steam.

#What is the linking -o- in words like lernolibro?

It is an optional vowel between two roots that makes the word easier to say or understand. It is the noun ending used as a joint, and it never takes -j or -n.

#Why does lernejo mean "school" and not any place for learning?

Like words in any language, Esperanto compounds get a fixed, conventional meaning. The parts give a strong hint; the dictionary gives the exact sense.

#Sources

• Fundamento de Esperanto – grammar in English (rule 11)
• Akademio de Esperanto – Akademia Vortaro, explanations and statistics
• Akademio de Esperanto – 10th Official Addition (2023)
• PMEG – Word-building principles
• PMEG – Compounds and front elements
• PMEG – Phrase words
• PMEG – Apparent compounds
• Reta Vortaro – lern/ (word family)
• uea.facila – La Unua Libro (917 roots)
• Wikipedia – Esperanto vocabulary
• Wikipedia – Plena Ilustrita Vortaro de Esperanto
• Vikipedio – Neceso kaj sufiĉo