In the grammar of Esperanto, words like “where”, “there”, “somewhere”, “when”, “then”, “sometime”, etc., are called correlatives. Esperanto has the broadest and most logical system of correlatives of all commonly spoken languages.
Let’s start with an example of a correlative that works in a way similar to English. In Esperanto, all correlatives related to a place end with an e, which is analogous to English here. By adding certain “prefixes” to this basis word, we get different meanings:
|Meaning||Esperanto prefix||with -e||English prefix||with -here|
|Close||ĉi ti-||ĉi tie||-||here|
Note that ĉi in the second row is written as a separate word, but you can think of the whole “ĉi ti-” group as a prefix (the difference between “ti-” and “ĉi ti-” is the same as between “that” and “this” in English”, i.e. “that place” and “this place”).
As you can see, the system works pretty well for “-here” in “English”, but it doesn’t fully work with other “suffixes”, such as -hen (as in “when” and “then”), which is -am in Esperanto:
|Meaning||Esperanto prefix||with -am||English prefix||with -hen|
(at that time)
|Close||ĉi ti-||ĉi tiam||-||then|
(at this time)
The beauty of the system lies in its regularity. Once you remember the six prefixes, all you need to know is the correct suffix. This does not necessarily make the words easier to use when you speak (as you need to recall them instantly), but if you have some time to think, you can never get them wrong—compare that with French and its lequel, celui-ci, cette, and similar, which are much harder to remember.
Let’s show one last example before giving the whole list of suffixes. The suffix equivalent to English -hat (as “what” and “that”) is -o:
|Meaning||Esperanto prefix||with -o||English prefix||with -hat|
|Close||ĉi ti-||ĉi tio||-||this|
There are 9 different suffixes that can be combined with the 6 prefixes shown in the table above. To better understand the concepts they express, let’s combine them all with ki- (question) and ti- (specific); the others are completely analogous:
for that reason
that way, so
who / which one*
The last two (marked with *) are somewhat harder to understand. “Kia” is used to ask questions about something when the expected answer is an adjective (ending with an -a) that describes it, e.g.
What is the weather like today?
The weather is good.
Another example is the proverb “like father, like son”: Kia patro, tia filo. The real meaning of the English version is “what the father is like, such is the son”, which could be translated as “kia estas la patro, tia estas la filo”.
When -a is combined with ĉi- (ĉia), i- (ia), and neni- (nenia), the resulting expressions can be translated as “every type (of)”, “some type (of)”, and “no type (of)”, respectively.
The suffix -u has two different meanings: First and foremost, it is used to refer to people (whereas -o is used to refer to objects), e.g.
Who is he? / What is it?
Everybody is sleeping. / Everything disappeared.
When a correlative with -u precedes a noun, it refers to a selection from a specific group. The easiest way to understand this concept is to look at kiu. “Kiu” means “which” (in the sense of “which one of”). For example,
Which dog is yours?
The implied meaning is that there is a group of dogs, and you ask someone which one is theirs.
Accusative and plural
The -o, -u, and -a correlatives substitute nouns and adjectives, and just like nouns and adjectives, they can be used in the plural (-j) and need an accusative marker (-n) when used as direct objects. For example:
What do you have there? / I have keys there.
Which dog does she want? / She wants all the dogs.
When the accusative marker is added to a place correlative (-e), the resulting correlative signifies direction rather than place:
tien – to there
ĉie – to everywhere
Anything, anywhere, whatever, etc.
You may have noticed that there were no words like “anything” an “anywhere” in the lists above. These correlatives do not have a separate prefix; instead, they are formed by adding the word ajn after the indefinite form:
iu ajn – any one
ie ajn – anywhere
When ajn is added to a question correlative (k-), it corresponds to English -ever, e.g.
kiu ajn – whichever / whoever
kie ajn – wherever