Grammar Index
Esperanto's grammar is famously concise — 16 rules, no exceptions. This section provides comprehensive reference material for each grammar topic, from core structures to advanced usage.
| Topic |
Description |
| Affixes |
All 9 prefixes (bo-, dis-, ek-, eks-, fi-, ge-, mal-, mis-, pra-, re-) and 18+ suffixes — the key to Esperanto's productive word-building system |
| Correlatives |
The complete 45-form table (ki-, ti-, ĉi-, neni-, i- × -o, -a, -e, -el, -al, -am, -es, -om, -u) with usage notes and examples |
| Verbs |
All 6 tenses/moods (-as/-is/-os/-us/-u/-i), 6 participles, compound tenses, transitivity, and voice |
| Nouns |
The -o ending, la article, plural -j, accusative -n, and expressing other cases with prepositions |
| Word Building |
How to combine roots and affixes, compound words, deriving multiple word classes from one root |
Grammar Quick Reference
Word Endings by Category
| Ending |
Category |
Example |
| -o |
Noun |
libro (book) |
| -a |
Adjective |
bona (good) |
| -e |
Adverb |
bone (well) |
| -i |
Verb (infinitive) |
paroli (to speak) |
| -as |
Verb (present) |
parolas |
| -is |
Verb (past) |
parolis |
| -os |
Verb (future) |
parolos |
| -us |
Verb (conditional) |
parolus |
| -u |
Verb (imperative) |
parolu! |
| -j |
Plural |
libroj (books) |
| -n |
Accusative |
libron (a/the book — direct object) |
Participle Endings
| Time |
Active |
Passive |
| Present |
-anta |
-ata |
| Past |
-inta |
-ita |
| Future |
-onta |
-ota |
Key Prefixes Summary
| Prefix |
Meaning |
Example |
| bo- |
in-law relationship |
patro→bopatro (father-in-law) |
| dis- |
dispersal, separation |
doni→disdoni (distribute) |
| ek- |
beginning of action |
dormi→ekdormi (fall asleep) |
| eks- |
former, ex- |
prezidento→eksprezidento (ex-president) |
| fi- |
moral disapproval |
homo→fihomo (scoundrel) |
| ge- |
both sexes together |
patro→gepatroj (parents: father+mother) |
| mal- |
opposite |
bona→malbona (bad) |
| mis- |
wrongly |
kompreni→miskompreni (misunderstand) |
| pra- |
primitive, great- |
patro→prapatro (ancestor, great-grandfather) |
| re- |
again, back |
veni→reveni (return) |
Key Suffixes Summary
| Suffix |
Meaning |
Example |
| -aĉ- |
poor quality |
domo→domaĉo (hovel) |
| -ad- |
continued/repeated action |
kuri→kuradi (to keep running) |
| -aĵ- |
concrete thing |
manĝi→manĝaĵo (food) |
| -an- |
member/inhabitant |
urbo→urbano (city dweller) |
| -ar- |
collective |
arbo→arbaro (forest) |
| -ĉj- |
masculine endearment |
patro→paĉjo (daddy) |
| -ebl- |
possible |
fari→farebla (doable) |
| -ec- |
abstract quality |
bona→boneco (goodness) |
| -eg- |
augmentative |
domo→domego (mansion) |
| -ej- |
place for/of |
lerni→lernejo (school) |
| -em- |
tendency/inclination |
labori→laborema (hardworking) |
| -er- |
individual unit |
sablo→sablero (grain of sand) |
| -et- |
diminutive |
libro→libreto (little book) |
| -id- |
offspring |
kato→katido (kitten) |
| -ig- |
make/cause |
pura→purigi (to clean) |
| -iĝ- |
become/intransitive |
ruĝa→ruĝiĝi (to turn red) |
| -il- |
instrument/tool |
tranĉi→tranĉilo (knife) |
| -in- |
feminine |
patro→patrino (mother) |
| -ind- |
worth doing |
vidi→vidinda (worth seeing) |
| -ing- |
holder/socket |
kandelo→kandelingo (candlestick) |
| -ism- |
-ism, doctrine |
paco→pacismo (pacifism) |
| -ist- |
professional/devotee |
muziko→muzikisto (musician) |
| -nj- |
feminine endearment |
patrino→panjo (mommy) |
| -obl- |
multiple |
du→duobla (double) |
| -on- |
fraction |
du→duono (half) |
| -op- |
group |
du→duope (in pairs) |
| -uj- |
container/country |
mono→monujo (wallet); Franco→Francujo (France) |
| -ul- |
person with quality |
rica→riĉulo (rich person) |
| -um- |
vague/idiomatic |
plena→plenumi (to fulfill) |
The PMEG Reference
For exhaustive grammar questions, the best free resource is PMEG — Plena Manlibro de Esperanta Gramatiko by Bertilo Wennergren. Available at bertilow.com/pmeg/. It covers every grammatical situation in extreme detail and is the standard reference for advanced learners.