The Sixteen Rules of Esperanto Grammar

Though Esperanto’s grammar is actually more complex than can be expressed in just sixteen rules, these are still of some interest. Besides these rules, any rules common to all Indo-European languages also apply to Esperanto, so that verbs can have direct objects, prepositions preceed their objects, adjectives modify nouns, etc.

For a more thorough grammar of Esperanto, consult «La Plena Manlibro de Esperanta Gramatiko», which is available on the World-Wide Web. This document is in Esperanto, so you’ll need to learn a bit of the language in order to get full use of it.

Here is the customary presentation of the rules, with my comments:

La dek-ses reguloj The Sixteen Rules

0 — Proper nouns are generally parts of other languages, and cannot be expected to follow all of Esperanto’s rules. I added this rule myself for completeness’ sake. Countries and many important cities have standardized Esperanto names, because they’re spoken of often enough that having these is useful. Besides, many have different names in different languages, anyway, such as Deutschland, Germany, Allemagne, Tyskland, Ashkenaz. Adding Germanujo to the list is no big thing.

A — The alphabet

Aa, Bb, Cc, Ĉĉ, Dd, Ee, Ff, Gg, Ĝĝ, Hh, Ĥĥ, Ii, Jj, Ĵĵ, Kk, Ll, Mm, Nn, Oo, Pp, Rr, Ss, Ŝŝ, Tt, Uu, Ŭŭ, Vv, Zz This table does not give the pronunciations of the letters, so see the alphabet page for the explanation. For some reason, this listing of the letters is not numbered among the rules.

B — Parts of speech

1 — There is no indefinite article; there is only one definite article, la, which is invariable. Note that you’re expected to know what an article is, and be aware that in many languages, there’s more than one word for “the”.

2 — Nouns (substantives), are formed by adding O to the root. To form the plural, J is added. There are two cases, nominative and accusative; the accusative is formed by adding N to the nominative. Equivalents of other cases are formed by the use of prepositions (e.g., de mia patro my father’s). You’re expected to know what a noun is, know what a root is, take for granted that nouns have plurals (and not all languages do), that there are such things as cases, and that you know what cases do.

3 — Adjectives are formed by adding A to the root. they agree in case and number with the noun they qualify, forming plural and accusative in the same way. The comparative is formed by the word pli, the superlative by plej. “Than” is rendered by ol. You’re expected to know what an adjective is, and what agreement is (not all languages have noun-adjective agreement), and that you know what comparative and superlative are.

4 — The basic cardinal numerals, which do not vary for case, are unu, du, tri, kvar, kvin, ses, sep, ok, naŭ, dek, cent, mil. Tens and hundreds are formed by simple junction of the numerals, e.g., 583 = kvincent okdek tri. Ordinals are formed by the addition of A, e.g., 4th = kvara. Multiples, fractions, and collective numerals are formed by the use of the suffixes –obl–, –on– and –op– respectively. Distributives are expressed with the help of the preposition po. Adverbials add E, e.g., firstly = unue. These rules leave out the number nul, zero. Cardinal numerals are simply counting-numbers, one, two, three, etc. Ordinals are words such as first, second, third, thousandth, etc. Multiples are words that mean once, twice, thrice, four times, etc. Fractions are the same as the ordinals in English, except for half, but have separate words in Esperanto. Collective numerals express groups, such as unuope one at a time, centope a hundred at at time, etc. The preposition po means at the rate of or per; see it described under prepositions.

5 — The personal pronouns are mi, vi, li, ŝi, ĝi, si, ni, ili, and oni. Possessive pronouns are formed by adding A. Declension as for nouns. See the pronoun section for the meanings of these.

6 — The verb undergoes no change with regard to person or number. Forms of the verb: time being (present) takes the termination −as; time been (past), −is; time about to be (future), −os; conditional mood, −us; imperative mood, −u; infinitive, −i. Participles (with adjectival or adverbial sense): active present, −ant−; active past, −int−; active future, −ont−; passive present −at−; passive past, −it−; passive future, −ot−. The passive is rendered by a corresponding form of the verb esti and a passive participle of the required verb. The preposition with the passive is de. See the verb section for these forms. Since the language was invented, it has grown another, simpler, passive form, using the suffix −iĝ−.

7 — Adverbs are formed by adding E to the root; comparison as for adjectives.

8 — All prepositions govern the nominative. This means that the basic noun form ending with O or OJ is the form that is used with prepositions, though some prepositions are also used with the accusative, the form that ends with ON or OJN, as covered in rule 13.

C — General rules

9 — Every word is pronounced as it is spelled. Pronounce every letter, even the groups considered unpronouncable in English, such as the beginnings of psiĥo and pneŭmonio, and pronounce the two Ns in finno differently than the single N in fino.

10 — The accent is on the next-to-last syllable.

11 — Compound words are formed by simple junction of roots (the chief word coming at the end). Grammatical endings count for this purpose as separate words [i.e., morphemes]. The part of the word at the end is the main part, with earlier parts modifying it: poŝ-mon-o = a noun: money in the pocket; but mon-poŝ-o = a noun: a pocket for carrying money.

12 — There is no multiple negation; if a clause contains another negative word, it needs no ne. In Esperanto, we don’t use no double negatives.

13 — To show motion towards, words take the accusative ending. This rule can be applied to objects of prepositions (en la akvon = into the water, rather than en la akvo = in the water), or to adverbs showing location (ĉi tien = to this place, rather than ĉi tie = here).

14 — Each preposition has a definite fixed meaning; but if the sense does not indicate which should be used, recourse may be had to the preposition je, which has no meaning of its own. Alternatively, the accusative without a preposition may be used. See the explanation of je in the section on prepositions. Technically, any preposition can be omitted and its object put into the accusative, but this practice can lead to ambiguities, so it should be used sparingly.

15 — The so-called foreign words, which the majority of languages have taken from one source, undergo no change in the International Language beyond conforming to its orthography. Derivatives, however, are preferably formed from one basic root according to the rules of Esperanto grammar. This, I believe, refers to trademarks and some similar nouns, which can be thought of as proper nouns. For example, we might speak of Microsoft^® without modifying the name, but we would esperanticize it to Mikrosofto before converting it to an adjective, mikrosofta.

16 — The A of the definite article and the final O of nouns may be dropped and replaced by an apostrophe. This is handy in songs and poems to get the right number of syllables, with the accented ones in the right places so that they scan. Note its use in the Esperanto Hymn. There are a few common expressions that use this rule, such as de temp’ al tempo = from time to time.

La dek-ses reguloj	The Sixteen Rules
0 — Proper nouns are generally parts of other languages, and cannot be expected to follow all of Esperanto’s rules.	I added this rule myself for completeness’ sake. Countries and many important cities have standardized Esperanto names, because they’re spoken of often enough that having these is useful. Besides, many have different names in different languages, anyway, such as Deutschland, Germany, Allemagne, Tyskland, Ashkenaz. Adding Germanujo to the list is no big thing.
A — The alphabet
Aa, Bb, Cc, Ĉĉ, Dd, Ee, Ff, Gg, Ĝĝ, Hh, Ĥĥ, Ii, Jj, Ĵĵ, Kk, Ll, Mm, Nn, Oo, Pp, Rr, Ss, Ŝŝ, Tt, Uu, Ŭŭ, Vv, Zz	This table does not give the pronunciations of the letters, so see the alphabet page for the explanation. For some reason, this listing of the letters is not numbered among the rules.
B — Parts of speech
1 — There is no indefinite article; there is only one definite article, la, which is invariable.	Note that you’re expected to know what an article is, and be aware that in many languages, there’s more than one word for “the”.
2 — Nouns (substantives), are formed by adding O to the root. To form the plural, J is added. There are two cases, nominative and accusative; the accusative is formed by adding N to the nominative. Equivalents of other cases are formed by the use of prepositions (e.g., de mia patro my father’s).	You’re expected to know what a noun is, know what a root is, take for granted that nouns have plurals (and not all languages do), that there are such things as cases, and that you know what cases do.
3 — Adjectives are formed by adding A to the root. they agree in case and number with the noun they qualify, forming plural and accusative in the same way. The comparative is formed by the word pli, the superlative by plej. “Than” is rendered by ol.	You’re expected to know what an adjective is, and what agreement is (not all languages have noun-adjective agreement), and that you know what comparative and superlative are.
4 — The basic cardinal numerals, which do not vary for case, are unu, du, tri, kvar, kvin, ses, sep, ok, naŭ, dek, cent, mil. Tens and hundreds are formed by simple junction of the numerals, e.g., 583 = kvincent okdek tri. Ordinals are formed by the addition of A, e.g., 4th = kvara. Multiples, fractions, and collective numerals are formed by the use of the suffixes –obl–, –on– and –op– respectively. Distributives are expressed with the help of the preposition po. Adverbials add E, e.g., firstly = unue.	These rules leave out the number nul, zero. Cardinal numerals are simply counting-numbers, one, two, three, etc. Ordinals are words such as first, second, third, thousandth, etc. Multiples are words that mean once, twice, thrice, four times, etc. Fractions are the same as the ordinals in English, except for half, but have separate words in Esperanto. Collective numerals express groups, such as unuope one at a time, centope a hundred at at time, etc. The preposition po means at the rate of or per; see it described under prepositions.
5 — The personal pronouns are mi, vi, li, ŝi, ĝi, si, ni, ili, and oni. Possessive pronouns are formed by adding A. Declension as for nouns.	See the pronoun section for the meanings of these.
6 — The verb undergoes no change with regard to person or number. Forms of the verb: time being (present) takes the termination −as; time been (past), −is; time about to be (future), −os; conditional mood, −us; imperative mood, −u; infinitive, −i. Participles (with adjectival or adverbial sense): active present, −ant−; active past, −int−; active future, −ont−; passive present −at−; passive past, −it−; passive future, −ot−. The passive is rendered by a corresponding form of the verb esti and a passive participle of the required verb. The preposition with the passive is de.	See the verb section for these forms. Since the language was invented, it has grown another, simpler, passive form, using the suffix −iĝ−.
7 — Adverbs are formed by adding E to the root; comparison as for adjectives.
8 — All prepositions govern the nominative.	This means that the basic noun form ending with O or OJ is the form that is used with prepositions, though some prepositions are also used with the accusative, the form that ends with ON or OJN, as covered in rule 13.
C — General rules
9 — Every word is pronounced as it is spelled.	Pronounce every letter, even the groups considered unpronouncable in English, such as the beginnings of psiĥo and pneŭmonio, and pronounce the two Ns in finno differently than the single N in fino.
10 — The accent is on the next-to-last syllable.
11 — Compound words are formed by simple junction of roots (the chief word coming at the end). Grammatical endings count for this purpose as separate words [i.e., morphemes].	The part of the word at the end is the main part, with earlier parts modifying it: poŝ-mon-o = a noun: money in the pocket; but mon-poŝ-o = a noun: a pocket for carrying money.
12 — There is no multiple negation; if a clause contains another negative word, it needs no ne.	In Esperanto, we don’t use no double negatives.
13 — To show motion towards, words take the accusative ending.	This rule can be applied to objects of prepositions (en la akvon = into the water, rather than en la akvo = in the water), or to adverbs showing location (ĉi tien = to this place, rather than ĉi tie = here).
14 — Each preposition has a definite fixed meaning; but if the sense does not indicate which should be used, recourse may be had to the preposition je, which has no meaning of its own. Alternatively, the accusative without a preposition may be used.	See the explanation of je in the section on prepositions. Technically, any preposition can be omitted and its object put into the accusative, but this practice can lead to ambiguities, so it should be used sparingly.
15 — The so-called foreign words, which the majority of languages have taken from one source, undergo no change in the International Language beyond conforming to its orthography. Derivatives, however, are preferably formed from one basic root according to the rules of Esperanto grammar.	This, I believe, refers to trademarks and some similar nouns, which can be thought of as proper nouns. For example, we might speak of Microsoft^® without modifying the name, but we would esperanticize it to Mikrosofto before converting it to an adjective, mikrosofta.
16 — The A of the definite article and the final O of nouns may be dropped and replaced by an apostrophe.	This is handy in songs and poems to get the right number of syllables, with the accented ones in the right places so that they scan. Note its use in the Esperanto Hymn. There are a few common expressions that use this rule, such as de temp’ al tempo = from time to time.

Questions or suggestions? Please write, and I’ll get back to you.

(Ĝisdatigita 23 februaro 2006)