The 16 rules of Esperanto compared with English

ESPERANTO	ENGLISH
1. There is no indefinite article. There is only one definite article, la, which is the same for all genders, cases, and numbers.	There are two indefinite articles, a, and an. 'An' is used when the word following begins with a vowel sound. There is only one definite article, the, which is the same for all genders, cases, and numbers.
2. All nouns take the ending '-o.' All plurals take the ending '-j.'  There are only two cases: nominative and accusative.  The accusative takes the ending '-n.'  Other cases can be expressed through prepositions: genitive 'de,' dative 'al,' ablative 'per,' etc.	Nouns carry no indication of part of speech.  Plurals are formed (not without exception) by '-s' (sounded as 'z') or, if the word in question ends with the s or z sound, then by '-es.'  The genitive case is shown by ('s), or if the word ends with an s, then by an apostrophe. Cases are generally shown by prepositions: dative 'to,' ablative 'via,' etc.
3. All adjectives take the ending '-a.' In case and number, adjectives are congruent with their substantives.  To make the comparative, 'pli' is used.  To make the superlative, 'plej' is used.  For expressions of comparison, the preposition 'ol' is used.	Adjectives carry no indication of part of speech.  Adjectives do not vary in number with their substantives.  To make the comparative, in some words, the article 'more,' and in some words the ending '-er' is used. Which words use which form must be individually learned. To make the superlative, in some words, the article 'most,' and in some words the ending '-est' is used. Which words use which form must be individually learned. For expressions of comparison, the preposition 'than' is used.
4. The cardinal numbers are not declined, and are unu, du, tri, kvar, kvin, ses, sep, ok, naŭ, dek, cent, mil. All numbers below one million are formed by joining these words.  For ordinal numbers, the adjectival ending is used.  For multiples, the suffix '-obl' is used.  For fractions, the suffix '-on' is used.  For rates, the preposition 'po' is used.  The numbers can be used as nouns and adverbs.	The cardinal numbers are not declined, and are one, two, three, four, five, six, seven, eight, nine, ten, hundred, and thousand. By tens: ten, twenty, thirty, forty, fifty, sixty, seventy, eighty, ninety. Between ten and twenty, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen. For ordinal numbers, the ending '-th' is used, with the exceptions that ordinal one is first, ordinal two is second, ordinal three is third, ordinal five is fifth, ordinal nine is ninth, ordinal twelve is twelfth. For multiples of ten, instead of '-ty,' '-tieth' is used.  For multiples, the suffix '-fold' and the expression 'by a factor of' are permitted. For fractions, the ordinal is used, except that two is half, four is quarter. For rates, the preposition 'per' or the phrase 'at a rate of' may be used. The numbers by themselves cannot be used as a noun. The numbers can be used as adverbs by the use of the ordinal, and the ending '-ly.'
5. Personal pronouns are mi, vi, li, ŝi, ĝi, si, ni, vi, ili, oni. Possessive pronouns are formed by the addition of the adjectival ending. Pronouns are declined as substantives.	Personal pronouns are I, you, he, she, it, we, you, they. Possessive pronouns are my, your, his, hers, its, our, your, their.  Object pronouns are me, you, him, her, it, us, you, them.
6. Verbs do not vary with person and number. Verb endings are: present '-as,' past '-is,' future '-os,' conditional '-us,' imperative '-u,' infinitive '-i.' Active participles are: present '-ant,' past '-int,' future '-ont.' Passive participles are: present '-at,' past '-it,' future '-ot.'	Regular verbs do not vary in person and number, except in the third person singular, present tense. In the present tense, regular verbs take the root, but in the third person, take the ending '-s.'  In the past tense, regular verbs take the ending '-ed.' In the future, regular verbs take the article 'will.' In the conditional, regular verbs take the particle 'would.' In the imperative, the root word is used. In the infinitive, the article 'to' is used. Which words use which form must be individually learned. Regular active participles take the ending '-ing,' and for tense, add the appropriate form of the irregular verb 'to be.' Exceptions must be individually learned. Regular passive participles take the ending '-ed,' and for tense, add the appropriate form of the irregular verb 'to be.' Exceptions must be individually learned.
7. Adverbs take the ending '-e.' Comparatives are the same as for adjectives.	Adverbs generally take the ending '-ly.' Comparatives will always be formed by more and most, but for many words, the ending will change to –lier or –liest. Which words use which form must be individually learned.
8. Prepositions always govern the nominative	Prepositions preceding pronouns govern the accusative form of the pronoun.
9. All words are pronounced as spelt.	English has no formally regularized spelling. The orthography still varies so widely that an exhaustive list could hardly be compiled. [In the United States, spelling bee competitions, premised on the fact that English words are hard to spell, are held in grade schools.]
10. The accent of every word falls on the penult (second to last syllable).	The accent of every word must be learned individually.
11. Compound words are formed by joining the root words, with the main word at the end. Suffixes and prefixes can be used as self-standing words.	Compound words can be formed by joining the words and dividing by a hyphen. Suffixes and prefixes very infrequently stand alone.
12. There is no double negative.	Use of the double negative is improper.
13. To show motion toward, the accusative is used.	To show motion toward, the word 'to' or 'toward' is used.
14. All prepositions have a fixed meaning. If no preposition is suitable, the preposition 'je,' which has no fixed meaning may be used, or the accusative without a preposition.	Most prepositions have narrow but non-literal meanings.
15. Foreign words may be received into Esperanto with no change except for conformity with the Esperanto orthography.	Foreign words may be received into English with no change except for conformity with the English alphabet and local pronunciation, or with no change, but italicized in print, or spoken slowly in speech.
16. The '-o' ending can be left off, and 'la' abbreviated (l').	Many elision devices are allowed for, among other things, poetic meter (eg. heaven = heav'n).

Contributed to the Public Domain, by Christopher Zervic, author, 2002.