Are there no "true" antonyms in Esperanto?

Question

I've just started learning Esperanto on Duolingo, and the only thing I don't like about the language is the formation of antonyms through "mal". It's not necessarily obvious to me why, say, "granda" is big and "malgranda" is small - or "kara" is expensive, but "malkara" is inexpensive/cheap (why not pick "cheap" as an adjective and then flip its meaning with "mal-", for example?)

Have Esperanto speakers ever created antonyms which stand on their own, without being derived morphologically from their counterpart?

Answer 1

Are there antonyms that don't being with -mal?

Yes, people (including Zamenhof) have created or do use (some) adjectives that can be seen as exact or approximate antonyms of other adjectives, and which aren't formed by prepending mal- to that other adjective.

In Esperanto, such words are sometimes called mal-mal-vortoj, which I find somewhat confusing, as mal-vorto could conceivably mean "antonym" and it'd seem that the opposite of an antonym could maybe be a synonym. However, in this expression, mal-vorto simply means vorto kiu komencas per mal-, so a mal-mal-vorto is a word that is an antonym of another one, but doesn't begin with mal-.

Some examples

According to the article / blog post Skalo de akceptiteco de mal-mal-vortoj by Markos Kramer, the most used mal-mal-vortoj in Tekstaro (an Esperanto literature corpus often used for analysis of the language) are, with their absolute number of occurences:

• stulta (≅ malsaĝa): 335
• amara (≅ maldolĉa): 146
• rara (≅ malofta): 142
• magra (≅ malgrasa, malabunda): 78
• olda (≅ maljuna): 71
• trista (≅ malgaja, malĝoja): 58
• povra (≅ kompatinda): 51
• dura (≅ malmola): 37
• frida (≅ malvarma): 30
• kurta (≅ mallonga): 30

(read the article for a more complete list)

In the article, the ratio between the mal-mal-vorto and its alternative mal-vorto(j) is use for another ranking, that tells us how popular the non-mal- antonym is in comparison to the synonymous antonyms built with mal-:

• amara / maldolĉa: 1,2586
• stulta / malsaĝa: 1,1242
• rara / malofta: 0,5035
• magra / (malgrasa + malabunda): 0,4815
• pigra / (maldiligenta+mallaborema): 0,4058
• dura / malmola: 0,1979
• povra / kompatinda: 0,1382
• trista / (malgaja + malĝoja): 0,0978
• lanta / malrapida: 0,0535
• olda / maljuna: 0,0444

What's the role of antonyms that don't being with -mal?

Some few of the mal-mal-vortoj are used regularly and accepted as common parts of the language. Others are more or less reserved for the following uses:

• poetic texts, e.g., song lyrics or poems
• convey a meaning that's slightly different from that of the corresponding mal-vorto(j)

Why don't more adjectives have commonly used mal-mal-vortaj antonyms?

This is an intended property of Esperanto. By its word-building system, its creator aimed to minimize the number of morphemes (word building blocks) one must learn to actively (speaking, writing) and passively (listening, reading) use the language. As many adjectives do have a clear and somewhat unambiguous antonym / opposite, the number of adjectives to be learned is almost halved by consistently building one member of each antonym pair with mal-. Take into account that some verbs and nouns also have sufficiently clear opposites, and the effect goes even beyond the number of adjectives.

Using mal-mal-vortoj instead of these would make the language harder to learn, due to a larger morpheme vocabulary, but not better to use, because the expressiveness and productivity of the vocabulary would stay the same.

In a pair of mutual antonyms, which should be the "base" word and which the mal-vorto?

It's not necessarily obvious to me why, say, "granda" is big and "malgranda" is small - or "kara" is expensive, but "malkara" is inexpensive/cheap (why not pick "cheap" as an adjective and then flip its meaning with "mal-", for example?)

It's sometimes said that Esperanto is based on logic and can be understood purely with logic. This is off course not really true, at least not completely. When one has an antonymous pair of meanings, and has to choose which one gets to be a base word with a proper root, and which one will be the derived one that gets the corresponding mal-vorto, the decision can (and in Esperanto not seldom does) seem somewhat arbitrary.

I myself sometimes trip over which of fermi and malfermi means "to close" and which "to open". And on a conceptual level, I'm somewhat annoyed that "left" and "right" aren't used symmetrically: The latter gets the proper root (dekstr·a) and the former usually "only" a mal-vorto (mal·dekstr·a). While the mal-mal-vorto liv·a exists, it's hardly ever used.

That being said, it's not like there's no rhyme and reason to most of those choices: Usually, the meaning that appears more fundamental gets the base word, and the other the derived one. Let's look at that criterium for the examples you gave:

big and small are both about size. When you list them in English, you most often do that in this order, rather than small and big, unless there's a specific reason (often for emphasis or contrast) to flip the order. Also, when you think about size, it it kinda synonymous with bigness. So quite clearly, big seems to be the more fundamental concept than small, which is rather the opposite of big.

cheap and expensive are both about price. The order argument doesn't really work here (I've listed cheap first and that doesn't seem strange or special at all), but if something is pricey, it's expensive, so maybe that one's the more fundamental direction on the price scale. Also, cheap can also be expressed as inexpensive, but I'm not aware of any "un-cheap"-like word construction for expensive.

It's worth noting that kara has other meanings (mostly valuable and dear/liked) that aren't related to price and that malkara doesn't seem to also express their antonyms. It's also wort noting, that for the price meaning, there are the commonly used kunmetaĵa synonyms multekosta (expensive) and malmultekosta (cheap, inexpensive) and the mal-mal-vorto ĉipa (cheap, inexpensive).

Off course, the notion of what is more fundamental in a pair of opposite meanings can be somewhat culture-dependant, but it seems to have turned out that actually, the sentiments of most cultures agree with most of Esperanto's choices w.r.t. mal- usage. There are also quite some clear antonym pairs, where mal- isn't customarly used for either member. They're probably also the pairs where there wouldn't be any widespread agreement over which member is the more fundamental one:

• tago & nokto
• mateno & vespero
• nord· & sud·
• okcident· & orient·
• (debatable) vir· & ·in·
• vintro & somero
• (debatable) printempo & aŭtuno

Answer 2

This is actually a broader question about word formation, how to build up words.

The site Bona lingvo has lists of same meaning words and among them are antonyms. A couple of frequent arguments are often presented to defend those words.

There are people who think that a certain word does not quite catch some meaning they perceive a word has. Native languages usually play a heavy role here.

In some cases the Esperanto expression is perceived to be too long or in some other way clumsy. A variant of this argument is, that mal- words get mixed up with their non-mal counterparts in a noisy or otherwise distracting environment.

Examples

Plaĝo means whatever kind of beach and you can say sabloplaĝo or sabla plaĝo to denote a sand beach, but some have created the word strando to exclusively refer to a sand beach.

Juna means young (of a person) and nova is new (of a thing). Their counterparts are obviously maljuna and malnova. Why can't there be one word for all aged, people and things alike, like olda?

The word malsanulejo consists of parts non-health-person-place and means a hospital, but wouldn't hospitalo be simpler?

We already have the verb fermi from French, so wouldn't it be handy to have ovri from French too instead of malfermi, because people often mix these fermi and malfermi?

Left is maldekstra, but is the prefix mal- audible in a noisy environment? Wouldn't liva therefore be a safer word for left?

PS. Kara has pretty much lost its meaning as "being expensive" and is contemporary used as Kara infano, kial vi ploras? : Dear child, why are you crying? or miaj karaj : my dear ones. As an adjective "expensive" one uses the word multekosta.

Are there non-mal-antonyms?

In another answer das-g refers to an article by Markos Kramer, which lists the most used mal-mal-vortoj. Noteworthy is the very low number of those compared to the size of Tekstaro (nowadays over 10 million words). So while such words have been proposed, they simply haven't won terrain. The mal- system effectively reduces the number of words to learn. It is also a known feature of languages to resist words that mean exactly the same, i.e. if a new word is adopted, it gets a meaning that somehow differs from the old word that describes the same phenomenon (see the "not quite catch" argument above).

It is not always obvious what an opposite to a word could be. While many agree that a day (in the sense of the bright part of a nychthemeron or tagnokto) and a night, north and south, west and east form opposites, there are no opposites for instance for colours, e.g. black is not malblanka or viceversa.

Selection of the "base" word

In addition to what das-g already wrote about this, I would like to add a point concerning fermi and malfermi. I think the reason for that choice is, that it is unambiguous when something is closed while there can be different degrees of being open. Think about a door. A closed door is a closed door, but an open door can be open so that the angle can be ajar or wide-open or anything between.

See a linguistic study Invented Antonyms: Esperanto as a Semantic Lab about the selection of the base words.