Esperanto conjunctions: kaj, sed, aŭ, ke, se, ĉar and more

Esperanto has 16 conjunctions on PMEG's lists: six coordinating ones that join equal parts (kaj, aŭ, sed, nek, plus, minus) and ten that open a subordinate clause (ke, ĉu, se, ĉar, kvankam, dum, ĝis, kvazaŭ, apenaŭ, ol). Fourteen come from the Fundamento (1905); plus and minus were added in 1974. They never change form and stand right before what they join or introduce.

#All Esperanto conjunctions

Status: Fundamento = the grammar and Universala Vortaro made binding in 1905; OA 8 = the Academy's Eighth Official Supplement. Dum and ĝis are also prepositions. Tamen "however" and tial "therefore" link ideas but are adverbs (adverbs, correlatives); unlike sed, they can move inside their clause.

#Joining equal parts: kaj, aŭ, sed, nek

• Kaj joins words, phrases or clauses of the same kind, never a main clause with a subordinate one (PMEG). In a list, commas replace kaj except before the last item: supon, salaton kaj fromaĝon – "soup, salad and cheese".
• Aŭ offers alternatives, usually "one or the other", sometimes "or both". PMEG advises against kaj/aŭ. After a negation aŭ works like nek: Li neniam fumas aŭ drinkas. – "He never smokes or drinks."
• Sed marks contrast, and after a negated part it gives the truth instead: Mi ne trinkas kafon, sed teon. – "I don't drink coffee but tea." It can open a sentence: Sed kio okazis poste? – "But what happened next?"
• Nek means "and also not" and follows a clause that already has ne or a neni- word: Mi ne vidis lin, nek ŝin. – "I didn't see him, nor her." It means only "and also not", never "not even" (that is eĉ ne, PMEG).
• Plus and minus are mostly arithmetic. Plus can also replace kaj for addition: dek eŭrojn plus kvindek cendojn – "ten euros plus fifty cents".

Four words also come in pairs. A doubled nek needs no extra ne (rule 12 of the 16 rules: one negative per clause).

#Subordinating conjunctions

• Ke only marks the start of a clause (PMEG), which never takes -n. After verbs of wanting, asking, ordering and advising the verb ends in -u: Mi volas, ke vi helpu. – "I want you to help." Facts use normal tenses: Mi scias, ke vi helpas.
• Ki- words (kiu, kie, kiam, kiel, kial…) open relative clauses and reported questions: Mi ne scias, kiam li venos. – "I don't know when he will come."
• Se with -as/-is/-os is a real possibility, with -us an imagined one: Se mi havas tempon, mi helpos. / Se mi havus tempon, mi helpus. – "If I have time, I will help." / "If I had time, I would help."
• Kvankam: when its clause comes first, the main clause often adds tamen: Kvankam mi estas laca, mi tamen laboras. – "Although I am tired, I still work."
• Dum is for two lasting actions at once, kiam for "when" in general.
• Ĝis needs a clause about a moment: Mi restis, ĝis li ekdormis. – "I stayed until he fell asleep."
• Kvazaŭ compares with something imagined, so its verb is usually -us. Apenaŭ clauses stand before the main clause.

#Combinations with ke and ol

Only five prepositions are generally accepted directly before ke: por, sen, anstataŭ, malgraŭ and krom (PMEG). With others add tio: pri tio, ke; for "because" and "before" see below.

With the same subject, antaŭ ol takes an infinitive: antaŭ ol manĝi. In ju … des, ju goes in the first part and des in the second, each with pli or malpli.

#Ĉar and pro tio ke

PMEG defines ĉar as "pro tio ke", so the meaning is the same; tial ke is a third equivalent. Ĉar is shortest, and a ĉar clause can also stand alone to explain the previous sentence. When it comes first, the main clause may start with tial: Ĉar pluvis, tial ni restis hejme. – "Because it rained, we stayed at home." Before a noun use the preposition pro: pro la pluvo. Tial means "for that reason", not "because".

#Ke, ĉu and se

Ke introduces a statement: Mi scias, ke li venos. Ĉu introduces a yes/no question inside a sentence and means "whether": Mi ne scias, ĉu li venos. A detail question uses a ki- word. See questions and negation.

English "if" covers both "whether" and "on condition that"; Esperanto separates them. Li diros, ĉu li venos – "He will say whether he is coming." Li diros, se li venos – "If he comes, he will tell us."

In reported speech the verb keeps the tense of the original words: Li diris: "Mi estas laca" becomes Li diris, ke li estas laca (PMEG). See verbs.

#Word order and commas

A conjunction stands right before what it joins. A subordinate clause can follow the main clause, precede it or sit inside it: Mi restas hejme, se pluvas. = Se pluvas, mi restas hejme. A ke clause can open the sentence too: Ke ŝi pravas, mi ne dubas. – "That she is right, I do not doubt." Inside the clause the order is as free as anywhere, but a ki- word or ĉu comes first (word order).

Esperanto has no binding comma rules (PMEG). Writers put one where a natural pause falls, usually before a subordinate clause and between joined main clauses: Ili manĝis, sed ili ne satiĝis. – "They ate, but they were not full."

#Mistakes learners make

#Examples in sentences

• Mi trinkas kafon, kaj mia edzino trinkas teon. – "I drink coffee, and my wife drinks tea."
• Ĉu vi volas teon aŭ kafon? – "Would you like tea or coffee?"
• Li estas juna, sed tre sperta. – "He is young, but very experienced."
• Mi havas nek tempon nek monon. – "I have neither time nor money."
• Mi scias, ke vi pravas. – "I know that you're right."
• Ŝi demandis, ĉu ni venos. – "She asked whether we would come."
• Se morgaŭ pluvos, ni restos hejme. – "If it rains tomorrow, we'll stay at home."
• Ni ne iris al la plaĝo, ĉar estis malvarme. – "We didn't go to the beach because it was cold."
• Kvankam li estis laca, li daŭre laboris. – "Although he was tired, he kept working."
• Mi skribas al vi, por ke vi sciu, ke ĉio estas en ordo. – "I'm writing to you so that you know everything is fine."

#Common questions

#How many conjunctions does Esperanto have?

Sixteen on PMEG's lists: six coordinating and ten that open subordinate clauses. Fourteen are in the Fundamento; plus and minus date from 1974.

#What is the difference between ĉar and pro tio ke?

None in meaning: PMEG defines ĉar as "pro tio ke". Ĉar is shorter, and its clause can also stand alone as an explanation.

#What is the difference between ke and ĉu?

Ke introduces a statement (Mi scias, ke li venos). Ĉu introduces a yes/no question inside a sentence (Mi ne scias, ĉu li venos).

#Is "if" se or ĉu in Esperanto?

Se is "if" for a condition; ĉu is "whether" in a reported question. Swapping them changes the meaning.

#Is there a comma before ke in Esperanto?

Usually yes, because a comma marks the natural pause before a subordinate clause. PMEG says there are no binding comma rules.

#Sources

• Fundamento – grammar in English (rules 3 and 12)
• Fundamento – Universala Vortaro
• PMEG – Kunligaj vortetoj (kaj, aŭ, sed, plus, minus)
• PMEG – Kombinitaj vortetoj (kaj … kaj, nek … nek, ĉu … ĉu, ju … des)
• PMEG – Subfrazoj (ke, ĉu, se, ĉar and other introducers)
• PMEG – ke after prepositions
• PMEG – Ĉar-frazoj
• PMEG – apenaŭ, dum, ĝis, kvankam, kvazaŭ, ol
• PMEG – Verb forms in reported speech
• PMEG – Negation (nek)
• PMEG – Word order and punctuation marks
• Vikipedio – Oka Oficiala Aldono (plus, minus, 1974)