The LojbanLanguage grammar is usually described using terms from lojban itself. Some claim that to do is is a needless barrier to newcomers understanding the language, and they have a point. The second part of this page is an attempt to give points for and against, but we'll start with a plain english description of most of the terms.

	'''The Book''':	Lojbanistani term for ''The Complete Lojban Language'' (When lojbanists are speaking English. ''The book'' would roughly translate into ''le cukta'' in lojban).

	'''bridi''':	Predication, the main kind of Lojban sentence, an assertion that some arguments (sumti) fill the places of a relation (selbri), or, in non-logician English, a statement of a relationship between items.

	'''brivla''':	Predication word (bridi valsi). A gismu, lujvo or fu'ivla (names, ''cmene'', are not brivla, neither are cmavo).

	'''cmavo''':	Structure word, like articles, pronouns, punctuation, AttitudinalIndicator''''''s, etc.

	'''cmene''':	Name, often referring to the ''jbocme'' (a lujvo meaning ''lojbanized name''). Names sometimes need to be lojbanized so that they only use valid lojban sounds and do not cause grammatical ambiguity, e.g. all Lojban names end in a consonant, thus names ending in a vowel can be lojbanized by adding a consonant (often 's') or by dropping the last vowel.

	'''fu'ivla''':	A lujvo meaning copy-word (from ''fukpi valsi''). A word 'borrowed' from one language to another, but 'borrow' implies we'll give it back, and copy-word sounds bad in English. Lojban fu'ivla consist of a rafsi attached to a lojbanized form of the original, the canonical example being djarspageti (dja = rafsi for cidja 'food') meaning spaghetti

	'''gismu''':	Root word. Five letters in the form CVCCV or CCVCV expressing a basic concept such a 'cat' (''mlatu'') or 'container with cap' (''botpi''). Can be used as a sumti (if prepended with a proper article) or selbri.

	'''le'avla''':	Archaic synonym for ''fu'ivla'' (from ''lebna valsi'', 'taken word')

	'''lojbangirz''':	The Logical Language Group, the organization in charge of lojban.

	'''lujvo''':	Compound word, usually made by sticking rafsi together, then given a fixed meaning (a place structure).

	'''malglico''':	An English-like Lojban construction (usually not meaning what the author originally intended, but ''malglico'' can also be used in other cases where knowing how to say something in English gets in the way of finding the proper way to express the same concept in Lojban).

	'''pro-sumti''':	cmavo that are used to abbreviate sumti. In a way a bit like English pronouns. Actually, ''pro-sumti'' is not a lojban term in itself, it is a mixed English/Lojban term for cmavo of selma'o KOhA. The term pro-sumti is frequently used in the reference grammar and the text book. 

	'''rafsi''':	Small (3 or 4 letter) form of a gismu used only in lujvo and fu'ivla, unambiguously referring to its gismu. E.g. ''fu'i'' in the lujvo ''fu'ivla'' is a rafsi for ''fukpi'' ('copy'), and ''vla'' is a rafsi for ''valsi''. 

	'''selbri''':	A relation with a set place structure, consisting of a defined relationship between sumti (from ''se bridi'', something that fill the second sumti place of the word 'bridi', i.e. the relation of the bridi).

	'''selma'o''':	Set of similar grammatically interchangeable cmavo (exchanging a cmavo in a sentence for another cmavo belonging to the same selma'o doesn't make the sentence ungrammatical, however, the meaning of the sentence will almost invariably change)

	'''sumti''':	An 'argument', something that fills a place of a relationship expressed in a bridi. A sumti is effectively a noun, pronoun, complex noun, complex pronoun, noun phrase, or complex noun phrase. It's a thing, however specified.

	'''tanru''':	Multiword selbri. Two or more brivla (predicate words) can form a tanru, i.e. a multiword selbri where the meaning of the brivla combine into a new selbri. The place structure of a tanru is the same as the place structure of the last brivla in the tanru. Eg. The lojban tanru ''blabi zdani karce'', 'white house car' (probably meaning 'white mobile home'), is still a kind of car, but a white house type of car (Lojban grammar is unambiguous, Lojban semantics are not, and the exact meaning of a tanru is usually determined by context). 

	'''valsi''':	Word, but some lojban cmavo correspond to punctuation in English or are attitudinal indicators that are really more like 'smileys' or a verbal form of indicating the speakers/authors feeling or attitude about something (without explicitly stating it in a bridi, which also is possible). E.g. ''.ui do klama ti'', 'You came here!' (indicating happiness about the fact), instead of saying: ''do klama ti .ije mi gleku la'e di'u'', 'You came here, and I am happy about that'.

OK, so each of these terms can be described in clear, unambiguous English, but discussions of any subject are always "empowered" by having short names for single concepts. The lojban grammatical concepts don't exactly match the English ones, so using the English terms requires at least one of inexactitude, elaborations, or risk of misunderstanding. 'Noun' is not a proper translation of ''sumti'' (even though many sumti can indeed be translated into an English noun). 'Noun phrase' is closer, but longer than 'sumti'. 'Compound word' is not a proper translation of ''lujvo''. In that case ''fu'ivla'' could then also be considered 'compound words' (formed from a rafsi and a lojbanized borrowed foreign word), but ''fu'ivla'' are not lujvo. Also the use of rafsi in lujvo construction make lujvo different from how compound words are formed in other languages.

In short, the lojban grammar unifies what in English are several distinct and disparate forms. As a result using the English grammatical terms is easier in the short term, but ultimately leads to more confusion than would otherwise be necessary.

For more information you might like to refer to the Lojban reference grammar. Essentially a final draft of ''The Complete Lojban Language'', the reference grammar is well written, in English, and not hard to read. Chapter 2 (http://www.lojban.org/jbo/publications/reference_grammar/chapter2.html), is a summary of the grammar and would probably answer most questions for those that are just curious and not looking into actually learning lojban. There is also a Lojban textbook available online at http://ptolemy.tlg.uci.edu/~opoudjis/lojbanbrochure/lessons/book1.html that might be more useful than the reference grammar to those that actually want to learn how to speak Lojban. 

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Criticisms of the original version of this page follow. Please, if they've now been answered or rendered irrelevant, remove them. If they've not been answered, please reword and highlight as appropriate.

''Unfortunately, it isn't more clear.  It's not like English grammatical terms are specific to discussing English - linguists have vocabulary for discussing things as different as Arabic, Chinese, Hopi and !Kung.  Is it really the case that Lojban can't be described in these same terms, or is it just that Lojban speakers aren't interested in discovering any correspondences?''

''For instance, you say "sumti" doesn't mean "noun", because it might include a modifier or consist of several words.  That sounds a lot like what linguists call a "noun phrase".  Are the two so completely different that to translate one as the other really loses meaning, or enough meaning that it's not worth giving non-Lojban speakers ''some'' idea of what's going on?  If so, are you sure there's no ''other'' grammatical terms that "sumti" might correspond to?''

Perhaps you can help us here, then.  A "sumti" is an argument to a predicate. Do you know of a linguistic term for that?  For example, in the lojban utterance "mi klama le zarci" we have a predicate word, "klama", which means "argument1 goes/went/will go to argument2"  In this case argument1 is "mi" and argument2 is "le zarci".  "mi" is filling the concept of an English subject, "le zarci" is filling the place of the English object.  However, in other examples (and a real lojbanist will have to help me out here) the predicate word argument places may not correspond to subject and object, and the arguments might not equate to English nouns. They often, perhaps usually, are nouns, simple or complex, abstract or concrete, but not always.

Giving English equivalents (and I'm not a linguist nor polyglot, so I don't want to speak beyond my ken) serves to make connections with English, but obscures the underlying consistency. One must beware of ''faux amis'' not just with words, but with structure.

''At the same time, you don't want technical details to obscure underlying similarity.  Polish and Chinese treat their nouns differently, but they are both still nouns.  If "sumti" are noun phrases 99% of the time, better to say Lojban has some new (presumably more consistent) ways of using noun phrases than to pretend they aren't akin.  While English may only use noun phrases as subjects and objects, that's not an inherent limitation on the term.''

''The thing is, people describe Lojban words in terms of English all the time.  "Sumti" are always described as "arguments" or "predicate arguments", seemingly without needing further qualifications.  It's obviously quite possible to discuss them using English words, the same way we talk about "attitudinals" instead of whatever Lojban calls them.  A good approach to discussing languages is to use English when possible, and only import foreign terms for a few truly unique constructs - which doesn't seem to happen very often.''

''From the Lojban pages here, it seems like the Lojban community is singularly reluctant to do this.  But it is not at all obvious to me why it couldn't be done, and that Lojban is different from English isn't enough.''

A linguist should probably answer the question on whether it is possible to use existing linguistic terms instead (and what terms that should be in that case). There might be suitable terms that could be used, and some people might consider it an advantage to use such English terms instead. It would however not be good if the English terms meant something different than the corresponding Lojban terms and this caused additional confusion. Like the contributor above, I am not a linguist either. Also English is not my native language (neither have I visited an English-speaking country), and thus, I am having some trouble even with the English grammatical terms. Perhaps that is why I do not really see a problem with using Lojban terms for discussing Lojban.

People define new words for new concepts all the time (or borrow words for other languages), nothing wrong about that. If anyone have a problem coming up with the correct grammatical terms when discussing a foreign language, the most natural solution would be to borrow and use the terms from that language. I believe some of the people of "The Logical Language Group" might be linguists. Anyway, they are certainly better at linguistics than I will ever be. Also, I think many of them are American. If they say that it is better to use the Lojban terms since the existing English terms doesn't mean exactly the same thing, I am not the person to argue. Anyone really interested in discussing Lojban would probably want to learn enough about the subject to know the meaning of these terms anyway.

Regarding the question of sumti being equivalent to nouns or noun phrases. Can events, properties, states, amounts, shapes, colors all be nouns or noun phrases? I admit I am uncertain regarding the definition of "noun phrase". According to dictionary.com, a''noun phrase'' is ''a phrase that can function as the subject or object of a verb''. What if it can not? Describing sumti as arguments, selbri as predicate and bridi as a predication would in my opinion probably be a better choice of terms. I am not a logician either, and thus I can not say for sure if these concepts from formal logic are completely equivalent to the Lojban terms, but these are the terms used in the reference grammar to explain the meaning of sumti, selbri and bridi. 

Now, there is still one other issue to consider. The Lojban community is still small. Once upon a time, probably many years ago, a choice was made to use Lojban terms to describe Lojban in English text. Some people might now consider this a bad decision, many do not, however this is the way Lojban has been described ever since. Nowadays there is a reference grammar that has been printed and published, there is a Lojban textbook, and there are other documents describing the language as well. All these use the Lojban terms to describe tha language. Changing this now is probably not realistic. Who would take on the task of rewriting all the documentation? Who would pay for the publication of a new edition of The Complete Lojban Language? And, if the documentation was not changed, wouldn't it just cause more confusion if people used different terminology when discussing the language online compared to the terminology used in the books? 

There are probably many more people speaking (or at least learning) Lojban today than it was when those decisions originally was made. Still, like in most communities, there are relatively few really active individuals leading the development of Lojban even today. There is also still a lot of work that needs to be done. There is still no complete Lojban dictionary and there is only a limited amount of texts that have been written or translated into Lojban. Those active individuals should probably spend their time working on getting new material written instead of trying to fix the minor problem of whether to use English or Lojban terminology when discussing Lojban.

Perhaps the used terminology should have been changed, but that should in that case probably have been done years ago, long before the language was baselined and the reference grammar and textbook had been written. Changing now would only create confusion and waste a lot of resources that are probably better spent on other tasks. Of course, if someone really had the motivation and knowledge to come up with an alternative English terminology for Lojban grammar and managed to get other people to use that terminology when discussing Lojban in English, that would probably be just fine. Which terminology the majority of people chose to use would then eventually determine which terminology is 'the right one'. 

''That's fine.  I personally would have preferred if the Lojban group tried to make things easy on people interested in comparing rather than speaking languages, but it's their choice.  I simply object to the claim that talking about Lojban in English would have been near impossible.  It doesn't seem likely, and doesn't follow from the descriptions above.''

It would probably not be impossible. It might have been inconvenient, it would probably mean minor redefinitions of some of the used English terms when they are used in the context of Lojban (which could be confusing). It might not be simple to get an English only description stringent enough for use in actually defining the language without losing clarity, but it would probably be possible if someone wanted to. Since Lojban is a ConLang, the grammar is the definition of the language, not only a description, and needs to be quite rigorous (formally it is the yacc machine grammar that is the official one, but the reference grammar still needs to be a precise definition since that is what people use to learn the language). 

Still, for the sake of comparison between languages. I wouldn't mind if someone managed to write a correct (and clear) description of Lojban using only terms normally used in linguistics. It probably wouldn't be easy (or someone would already have done it). I certainly couldn't do it, being an amateur learning Lojban just for fun, but I agree there sure would be interesting to know if Lojban is similar to anything else out there (except the original Loglan that is, we know Loglan and Lojban are related).