The Sixteen Rules of Esperanto Grammar
- with expert advice from Don Harlow

The Sixteen Rules

 1. Articles
 2. Nouns
 3. Adjectives
 4. Numerals
 5. Pronouns
 6. Verbs
 7. Adverbs
 8. Prepositions
 9. Pronunciation
11Compound Words
14. The Multipurpose Preposition
15Borrowing Words

Some Postnotes by Harlow

A. Word Order
B. Transitivity
C. Progression of Tenses
D. Desambiguation with -N

In the following paragraphs Zamenhof’s rules are in italics; bracketed expressions are [editorial interpolations];  other notes are commentary by myself.  All added material is in plain text.

EXAMPLES are created by myself, Don Harlow, and are shown in blue

1. There is no indefinite ARTICLE [English ‘a’, ‘an’];  there is only a definite article la, alike for all genders, cases and numbers [English ‘the’].

Author’s [i.e. Zamenhof] Note: The use of the article is as in other languages. People for whom use of the article offers difficulties [e.g. speakers of Russian, Chinese, etc.] may at first elect not to use it at all.


libro book, a book
la libro the book   

The main difference between the use of the definite article in Esperanto and in English is that in Esperanto the article, with a singular noun, may be used to indicate an entire class.


la leono estas danĝera besto
lions are dangerous animals

2.  NOUNS  To form the plural, add the ending -j [like ‘y’ in English]. There are only two cases: nominative and accusative; the latter can be obtained from the nominative by adding the ending -n.  The other cases are expressed with the aid of prepositions (genitive by de [English ‘of’], dative by al [English ‘to’], ablative by per [English ‘by means of’] or other prepositions, according to meaning).

La hundo persekutis la katojn de la knaboj al la domo per bojado
The dog chased the boys’ cats to the house by barking.’

3ADJECTIVES end in -a.  Cases and numbers are as for nouns.  The comparative is made with the word pli [English ‘more’], the superlative with plej [English ‘most’]; for the comparative the conjunction ol [English  ‘than’] is used.

La bruna hundo persekutas la nigrajn katojn
The brown dog is chasing the black cats
La bruna hundo estas pli granda ol la nigraj
The brown dog is bigger than the black cats.
Sed la homo estas la plej granda el ĉiuj
But the human being is the largest of all.

4.  The basic NUMERALS (not declined) are:  unu, du, tri, kvar, kvin, ses, sep, ok, naŭ, dek, cent, mil [English ‘one’, ‘two’, ‘three’, ‘four’, ‘five’, ‘six’, ‘seven’, ‘eight’, ‘nine’, ‘ten’, ‘hundred’, ‘thousand’].  Tens and hundreds are formed by simple juxtaposition of the numerals. To show ordinal numbers we add the adjective ending; for multiples, the suffix -obl; for fractions [actually, reciprocals]-on; for collectives -op; for the distributives [the particle] po.  Noun and adverb numerals can also be used.


Mil naŭcent naŭdek kvin 1995.
La kvina trono The fifth throne.
Duobla eraro A double error
Tri kvaronoj Three quarters.
Duopo A pair.
Mi donis al ili po tri pomojn I gave them three apples each.

The particle po causes many problems for beginning speakers of Esperanto, particularly those whose native language is English.  

First, there is a tendency to put ‘po’ with the wrong noun:

EXAMPLE – not correct

*Mi rapidis cent kilometrojn po horo  I was speeding along at a hundred kilometers an hour – is wrong!   ‘Po’ means ‘at the rate of’ and like the ‘@’ sign in English should be placed as follows:

EXAMPLE – this is correct
Mi rapidis po cent kilometrojn en horo
I was speeding along at a hundred kilometers an hour.

Second, since the objects of prepositions generally don’t take the -n ending in Esperanto, there’s a tendency to assume that in a sentence like the example above the -n on the object shouldn’t be there!

EXAMPLE – and this is correct
Mi donis al ili po tri pomojn – I gave them three apples each

Remember that po always takes as its object a numeral.  Any associated noun takes whatever it would have if the po weren’t there at all.  Mi donis al ili pomojn [po tri (al ĉiu)].  I gave them apples [at the rate of three (to each)].


5.  Pronouns

Personal PRONOUNS:  mi, vi, li, ŝi, ĝi (for an object or animal), si, ni, vi, ili, oni

[English has ‘I’, ‘you’, ‘he’, ‘she’, ‘it’, ‘oneself’, ‘we’, ‘you’, ‘they’, ‘they’ or ‘people’ or ‘you’].  The possessive pronouns are formed by addition of the adjective ending.  Declension is as for nouns.


Mi amas vin  I love you.
Mia hundo amas vian katon  
My dog loves your cat.
Mi razas min kaj vi razas vin  I shave myself and you shave yourself.
Sed la hispana barbisto razas sin
But the Spanish barber shaves himself.
Oni diras, ke li amas ŝin
It is said (they / people say) that he loves her.

Zamenhof also created a second-person-singular pronoun ci [English ‘thou].  It does appear in the ‘Fundamento’, Esperanto’s quasi-bible, its ‘foundation stone’.  It is occasionally used in poetry for effect, and in the word ci-diri — to speak to someone in an intimate fashion a la French or German

Some Esperanto speakers feel the need for a non-gender-specific singular pronoun to refer in the third person to human beings.  Zamenhof recommended that the word ĝi simply be used for this.  A few Esperanto speakers, however, primarily native speakers of English, feel uncomfortable with this usage and have come up with a new pronoun ri (“he/she”).  It is rarely used and you are not likely to encounter it.  Liŝiŝili and ŝli have also been used experimentally in this way, ŝli most frequently.  You won’t encounter them, either.

Some other Esperanto speakers would prefer to have a specifically female third-person plural pronoun.  The word iŝi has been used for this.  Again, you are unlikely to encounter it.


The VERB does not change for person or number.  Forms of the verb: present time takes the ending -as; past time, -is; future time, -os; conditional mood, -us; command mood, -u; infinitive mood, -i.

Participles (with adjectival or adverbial meaning): present active, -ant; past active, -int; future active, -ont;
present passive, -at; past passive, -it; future passive, -ot

All forms of the passive are formed with the aid of the corresponding form of the verb esti (English to be) and
the passive participle of the required verb; the preposition with the passive is de (English by).


Mi amas vin = I love you.

Mi amis vin

= I loved you (but don’t any longer, or it’s irrelevant to
what’s happening now).

Mi amos vin

= I shall love you (but haven’t started yet, or it’s irrelevant to what’s happening now).

Se vi gajnus la loterion, mi amus vin

= If you were to win the lottery, I would love you (but
that’s not likely).

Mi deziras, ke vi amu min; do amu min!

= I want you to love me; so love me!

Koni lin estas ami lin

= To know him is to love him.

It’s probably worth noting that the Esperanto time-sense is
slightly different from that of English. If something as shown in the present tense (-as), it is assumed to be happening, and of interest, at the moment the sentence is expressed; if it is
shown in the past tense (-is), it is assumed to be either completed or no longer of interest. If it is shown in the
future (-os), it is assumed to be either not yet begun or not yet of interest. (This view of time and completion carries over into the participles as well.)  So in a few cases when in English
something might be expressed as having happened in the past, in Esperanto it would be shown in the present, assuming that it is still going on and still of interest.


Mi loĝas ĉi-tie jam kvin jarojn

= I have been living here for five years already.

For examples of how participles are formed, see the affixes
page.  Participles are more accurately adjectives formed from action roots than parts of the verb — a situation somewhat different from that in English.

I use the term “command mood” instead of the more
common “imperative mood” to translate Zamenhof’s modo ordona, since -u covers a much wider range of uses
than the traditional Western imperative; in fact, it takes on many of the jobs ordinarily done by the subjunctive (which does not exist as a separate entity in Esperanto — for which generations of Latin students may give thanks!).  Kalocsay and Waringhien refer to this form, in the Plena Analiza Gramatiko, as the “volitive mood.”

The Bulgarian Esperantologist Atanas Atanasov denies the
existence of passive verb forms in Esperanto — and I find myself agreeing with him.  Use of the participial suffixes may be better understood if you consider them as means of transforming verbs into adjectives, not as parts of speech in
themselves.  The Western passive voice is shown, as Zamenhof says, by coupling the verb esti = to be with the “passive participles”; but these are not really compound verb forms, merely the copula linked with an adjective.


La sandviĉo estis manĝata

= The sandwich was (in a state of being) eaten.

La sandviĉo estas manĝita

= The sandwich is (in a state of having been) eaten.

La sandviĉo estis manĝita

= The sandwich was (in a state of having been) eaten.

La sandviĉo estos manĝota

= The sandwich will be (in a state of) going to be eaten.

Use of such forms is rare in Esperanto — even rarer than
it is in English, where Strunk & White advise against them. Ordinary passives can easily be converted into ordinary active sentences in Esperanto, msometimes with the inversion that the -nmending permits, and the pronoun oni makes translation of even agentless passives as active very easy.

William Auld, in his 100-page epic poem La Infana Raso, doesn’t use the passive once. Bureaucratese is rare in Esperanto.


La katon persekutis la hundo = The cat was chased by the dog.

Oni pafis la hundon = The dog was shot.

[Adverbs] end in -e; comparison is as for adjectives.
La kato rapide kuris
= The cat ran fast.
La hundo pli rapide kuris ol la kato
= The dog ran faster than the cat.
Sed la gepardo plej rapide kuris el ‡iuj
= But the cheetah ran fastest of all.

All PREPOSITIONS take the nominative.
La libroj de la knabo
= The boy’s books (the books of the boy).
Mi faris tion por vi
= I did that for you.
Floroj kreskas ‡irkaß mia domo
= Flowers grow around my house.
Prepositions of location may also take objects with the -n ending to show motion to that
location; this follows from rule 13.
La muso kuris sub la tablo
= The mouse ran (around) under the table.
La muso kuris sub la tablon
= The mouse ran (to) under the table.
While the particles anstataß (instead of) and krom (besides, in addition to) are
generally classified (by analogy with their equivalents in Western languages) as
prepositions, their behavior is more like that of coördinating conjunctions such as kiel.
So many Esperanto speakers will add the -n ending to the objects of these
“prepositions” when they coordinate with another word that has an -n ending.
Mi amis ×in anstataß li = It was I, not he, who loved her.
Mi amis ×in anstataß lin = I loved her, not him.

Every word is read as it is written. This should make immediate sense. [edit]



The ACCENT always falls on the next-to-last syllable (vowel). When accenting a noun with an elided -o, the accent always falls where it would if the -o were still there. For elision, see rule 16.


[Compounds] are formed by simple juxtaposition of words (the main word stands at the end); the grammatical endings are also viewed as independent words. Depending upon the sound produced when the two words are put together, the speaker may wish to insert a vowel between the two. If this is done, the vowel should be an o if the leading word is an object, or an i if the leading word is an action. Purists might also wish to put in an n if the trailing word is an action acting on the leading word, but this is not

ŝipo (ship) + veturi (travel)
= ŝip(o)veturo (a journey by ship)
ami (to love) + plena (full)
= am(o)plena (full of love)
pagi (to pay) + povi (to be able)
= pag(i)pova (able to pay)
nenio (nothing) + fari (to do)
= neni(o(n))fara (doing nothing)

12. [NEGATION] When another NEGATIVE word is present, the word NE (English no, not) is omitted. EXAMPLES Mi ne faris tion = I didn’t do that. Mi neniam faris tion = I never did that. ——-


13. To show DIRECTION, words take the accusative ending.

      The n ending is used to show the destination of a motion or the 
      direct recipient of an action. To show the accusative (direct 
      object) case is only one of its uses.

         La reĝino iris Londonon 
            = The queen went to London.
         La kato saltis sur la tablon 
            = The cat jumped onto the table.

      When an action and a movement occur in the same expression and 
      confusion is otherwise unavoidable, the n ending is used only for 
      the action, while the preposition al is used for the movement.

         Mi ĵetis la katon sur la tablon 
            = I threw the cat onto the table. (preposition does away with any confusion)
         Mi sendis al li la leteron 
            = I sent him the letter. (Mi sendis lin la leteron would be confusing)

14. Every preposition has a definite and permanent meaning, but if we have to use a preposition and the direct meaning doesn’t tell us what preposition we should take, then we use the preposition JE, which has no independent meaning. Instead of je the accusative without a preposition may be used.

         Li vetas je la ĉevaloj 
            = He bets on the horses.
         Mi alvenos je la oka horo 
            = I'll arrive at eight o'clock (the eighth hour).
         Li vizitos nin je lundo 
            = He'll visit us on Monday.
         Li lundon vizitos nin 
            = He'll visit us on Monday.

      Since this rule gives us permission to use the -n ending instead 
      of the preposition je, some Esperanto speakers also assume that it 
      permits us to use the preposition je instead of the -n ending. 
      This is a convenience when we encounter a word (such as a proper 
      name) which doesn't lend itself well to taking a regular Esperanto 

         Mi ja konas Glazunovski-on 
            = I do know Glazunovski.
         Mi ja konas je Glazunovski 
            = I do know Glazunovski.

      An honorific can also be used to get around this problem.

         Mi ja konas sinjoron Glazunovski 
            = I do know Mr. Glazunovski.

[Adverbs] end in -e; comparison is as for adjectives.
La kato rapide kuris
= The cat ran fast.
La hundo pli rapide kuris ol la kato
= The dog ran faster than the cat.
Sed la gepardo plej rapide kuris el ‡iuj
= But the cheetah ran fastest of all.

All PREPOSITIONS take the nominative.
La libroj de la knabo
= The boy’s books (the books of the boy).
Mi faris tion por vi
= I did that for you.
Floroj kreskas ‡irkaß mia domo
= Flowers grow around my house.
Prepositions of location may also take objects with the -n ending to show motion to that
location; this follows from rule 13.
La muso kuris sub la tablo
= The mouse ran (around) under the table.
La muso kuris sub la tablon
= The mouse ran (to) under the table.
While the particles anstataß (instead of) and krom (besides, in addition to) are
generally classified (by analogy with their equivalents in Western languages) as
prepositions, their behavior is more like that of coördinating conjunctions such as kiel.
So many Esperanto speakers will add the -n ending to the objects of these
“prepositions” when they coordinate with another word that has an -n ending.
Mi amis ×in anstataß li = It was I, not he, who loved her.
Mi amis ×in anstataß lin = I loved her, not him.

16. The FINAL VOWEL of the noun and the article may be dropped and replaced by an apostrophe [without effect on stress].

         L' espero, l' obstino kaj la pacienco... 
            = Hope, stubbornness and patience...
         Ho, mia kor', ne batu maltrankvile... 
            = Oh, my heart, do not beat nervously...

      N.B. The noun ending may be elided only if it does not have a 
      plural or accusative ending attached to it!

15. The so-called FOREIGN WORDS, i.e. those taken by the majority of languages from one source, are used in Esperanto without change, taking on only the orthography of this language; but for different words from a single root it is better to use without change only the basic word, and form the rest from this latter according to the rules of Esperanto.

         lakso = diarrhoea
            konstipo = constipation <-- borrowed
            mallakso = constipation <-- internally created
         bona = good
            mava    = bad <-- borrowed
            malbona = bad <-- internally created
         komputi = to compute
            komputero = computer <-- borrowed
            komputilo = computer <-- internally created
         arbo = tree
            forsto = forest <-- borrowed
            arbaro = forest <-- internally created
         ami = to love
            hati   = to hate <-- borrowed
            malami = to hate <-- internally created
         dis = in various directions (prefix)
            separi  = to separate <-- borrowed
            disigi  = to separate <-- internally created

      There has been much dialectic about this topic during the history 
      of Esperanto. For two good polemical accounts (from opposite 
      sides) see Claude Piron's La Bona Lingvo (The Good Language) and 
      Fernando de Diego's Pri Esperanta Tradukarto (On the Art of 
      Translation in Esperanto).  What Zamenhof means by "the majority 
      of languages" is no longer as clear as it was a hundred years ago.


Here follow some comments on Esperanto grammar that fall outside the explicit descriptions of the basic 16 rules.

A.  Word Order

Rules 2, 3, 6 and 7 above show one of Esperanto’s fundamental differences from English: its use of grammar-coding for showing the roles that words play in a sentence.  English does the same thing, but not with the same consistency (the common adverbial ending -LY occasionally shows up in adjectives, as friendly, and conversely the ending -WISE is often used today); and furthermore the primary English grammatical ending (-S, often pronounced -Z) is heavily overloaded, being used for the plural, the genitive case, and the third person present singular of the verb.  For all intents and purposes these endings in English are fossilized, and could be lost without much loss of meaning.  English depends heavily on word order to give a sentence proper meaning.

Speakers of Esperanto often brag that their language has been freed from the chains of word order.  This is an exaggeration.  Rule 8, for instance, implies that nouns are sometimes linked together by prepositions, and the very name preposition indicates that its noun object must follow the preposition, as in English (though not Japanese, where postpositions are used, and the object of the postposition must precede the postposition).  Similarly, Esperanto adverbs, which can modify a variety of different types of words, should always precede the word they modify.  This is particularly important for such words as neankaŭnur and one or two other particles usually (and perhaps incorrectly) described as adverbs which can be associated with nouns as well as the usual verbs, adjectives and other adverbs.

But the claim still contains much truth.  There are two basic forms of word order that are much freer in Esperanto than in English.  The first of these is the order of a noun and its adjective modifiers.  An adjective in English must be placed before the noun it modifies (with the occasional exception, as when you are trying of a “pseudo-archaic” atmosphere).  An adjective in Esperanto may be placed before or after the noun it modifies, and can even be separated from it by other words, if this will not cause any ambiguity.  As an example, while the object of a preposition must follow the preposition, in Esperanto as in English, adjectives modifying that object may even be placed before the preposition, as in the following translation from the poetry of Matthew Arnold:

Kaj altas montosuproj, nuba en aer’…(And high the mountaintops, in cloudy air…)

…where the word nuba (“cloudy”) is placed before the preposition for reasons of scansion.  This degree of freedom (some may call it “license”) is usually exercised only in poetry, of course. 

The other, and more important, occasion in which word order is freer in Esperanto than in English has to do with the order of subject, object and verb. In English, in almost every situation subject must precede verb which then precedes the direct object.  In Esperanto all six possible permutations of these elements are permissible and used:

The boy bit the dog (1) La knabo mordis la hundon  (2) La knabo la hundon mordis  (3) La hundon la knabo mordis  (4) La hundon mordis la knabo  (5) Mordis la hundon la knabo  (6) Mordis la knabo la hundon

The first of these is the most commonly used (and pedestrian) word order in Esperanto, probably because it is the standard word-order in the languages spoken natively by most Esperantists.  On the other hand, the fourth is probably the second most popular, despite the fact that it is standard word-order in almost no ethnic language in the world, probably because of the ability it gives to emphasize the direct object.  The second and sixth are not terribly widely used, despite the fact that they are used as standard word orders by several different languages (Latin, German, Japanese in the first case, Irish and all other Celtic languages in the second).

Is there any value in this ability to vary word order?  English, after all, does very well without it.  Well, perhaps not so well — one of the major reasons for any preoccupation with a journalistic, Hemingwayesque style of writing in which sentences are short and choppy, and contain relatively few modifiers, is that it is very hard in modern English to write sentences that are both complex and easy to follow.  It can be done, but it requires much care and effort.  The job is considerably easier in Esperanto.  I suspect that it is no coincidence that the accusative case disappeared from the Western vernaculars during a period of low literacy and little literature!

When you speak Esperanto, feel free to vary your word order as you see fit, where the rules permit.

B.  Transitivity

Transitivity refers to the ability of a verb to accept a direct object.  Some verbs can and some verbs can’t, in both English and Esperanto.

A problem that often arises for speakers of English (and some other languages) is the case in which two related verbs, one transitive and one intransitive, have identical forms in English.  Two common examples are “to burn” and “to drown”.  Both of these verbs can be both intransitive and transitive.  The meanings, of course, are somewhat different:

The fire is burning  The fire is burning the house  I am drowning  I am drowning the cat

In Esperanto, a verb in its basic form refers to one and only one action — a transitive one or an intransitive one.  You can convert the one to the other with the suffixes -IG (intransitive->transitive) and -IĜ (transitive-> intransitive) (see the affixes page).  In the above examples we have:

La fajro brulas  La fajro bruligas la domon   Mi dronas   Mi dronigas la katon

The problem arises when learning the words through the medium of English.  It is often difficult to remember whether the word that means “to drown” means “to die of suffocation in liquid” or “to kill by suffocating in liquid”.  When you encounter such words, it is best to remember their meanings — not their English language equivalents.  

C.  Progression of Tenses

In English and other Western languages, when a subordinate clause is attached to a sentence, the tense of the verb in the subordinate clause depends on the tense of the verb in the main body of the sentence, as in:I know that he will come…I knew that he was going to come…I wonder whether he will come…I wondered whether he would come… In Esperanto, for subordinate clauses beginning with ke (“that”) and ĉu (“whether”) the tense of the verb in the subordinate clause is independent of the main clause: it will always be the tense as seen by the subject of the main clause, whatever time frame that happens to be in: Mi scias, ke li venos…Mi sciis, ke li venos…Mi scivolas, ĉu li venos…Mi scivolis, ĉu li venos… For reasons I have never figured out, the same simple rule is not followed for subordinate clauses that begin with one of the correlatives; most Esperantists use a progression of tenses like those in Western languages for these. I don’t know when he’s coming…I didn’t know when he was going to come…Mi ne scias, kiam li venos…Mi ne sciis, kiam li estis venonta… Still, this is not a rule, and as far as I know you are free (and will find it a lot easier) to follow the simple rule: “Use the real tense” as with ke and ĉu.

D.  Desambiguation with -N

The ability to distinguish between subject and object via the -N ending not only allows greater freedom of word order, but also allows us, in some cases, to remove potential ambiguities when a coordinated noun’s relationship to the original noun is either tacit or indeterminable. A good example of what this means is the sentenceHe treated me like a prince What does this mean? That he wined me and dined me? Or that he ordered my head lopped off? Well, all us native English-speakers know that the first is correct — because the entire expression is basically an idiom, its meaning more or less free of the meanings of the words contained. Unfortunately, the meaning may be less clear to the non-native speaker. In Esperanto, this sort of sentence is easily handled. In the first case Li traktis min kiel princon where the -N on the end shows that the noun coordinates with “min”. On the other hand, if we should (for some reason) wish to express the second case, we can use Li traktis min kiel princo where the lack of a final -N shows that the noun coordinates with “li”. An earlier example was given in rule 8 for the words anstataŭ and krom.

Donald J Harlow ( 1942 – 2008) was an active well-esteemed Esperantist in the USA.  He authored a self-published book on the Esperanto movement, The Esperanto Book (1992), which was available online.  He also created at similar dates online an extensive index of Esperanto literature.