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TANRU AND LUJVO-MAKING
tanru are Lojban metaphors. They are made up of gismu representing concepts that are related to the concept being communicated. The relationship isn't necessarily unambiguous in meaning, although the grammatical relationship between the words is unambiguous. A blue-nest in some way nests someone or something. It could be a nest for blue eggs, or blue people, or it could be a house painted blue either partially or completely. It takes a more elaborate tanru to distinguish these less ambiguously (if such is important), or non-tanru methods can be used to expand communication unambiguously. Most often, tanru will be appropriate. tanru are something like English adjective-noun and adverb-verb combinations. They go beyond these concepts by combining and expanding upon them. In this, they are similar to Chinese metaphor more than to English. In general, the gismu on the left modify those on the right, and all groupings are in pairs from the left. Thus
broda brode brodi brodo brodu
is a 5-part tanru. The meaning is interpreted by grouping gismu in pairs as:
(((broda brode) brodi) brodo) brodu
To change this unambiguous grouping, specific cmavo are used that allow unique expression of the possible groupings. The cmavo 'bo' causes two adjacent gismu to group together before any other groupings. Thus we get
((broda brode) (brodi bo brodo)) brodu
If there are two bo's in a tanru, the leftmost takes precedence, but this is unlikely to occur in normal usage. The cmavo 'ke' can be used to change the grouping. ke causes everything to the left of it to modify everything to theright; an example is:
broda ke (((brode brodi) brodo) brodu)
To terminate right-grouping before the end, close off with ke'e, the rightgrouping terminator cmavo:
(broda ke ((brode brodi) brodo) ke'e brodu)
The logical connectives and negation can be used to modify part or all of a tanru. The tanru logical connective cmavo are ja, je, jo, ju, and each of these can be negated using na (negates the term before the connective) and nai (negates the term after the connective). In addition, the mixed connectives of selma'o JOI and the abstraction cmavo of selma'o NU can modify the components of tanru, and numbers can be incorporated into tanru with the aid of selma'o MOI.
tanru-making is one of the most important skills in speaking Lojban, because tanru are the primary source of semantic ambiguity in the language. The essence of tanru interpretation depends on imaginatively thinking of possible meanings (using some simple conventions to limit the possibilities), and then determining why the speaker used this particular tanru as opposed to some other, thus weeding out the interpretations that are not intended by the speaker. To make a new tanru, the reverse process is used. Think of a few possibilities, then try to analyze how a listener might misinterpret each possibility. Thus, making tanru gets to the true essence of human communication: putting one's self in the mind of the other person, and figuring out what that mind is thinking. When thinking Lojbanically - seeing the world through tanru - one is to some extent practicing a form of mind-reading.
The following are two of the most basic of the tanru conventions:
Given a tanru which expresses an idea to be used frequently, it can be turned into a lujvo by following the lujvo-making algorithm. In building a lujvo, the first step is to replace each gismu with a rafsi that uniquely represents that gismu. (Some cmavo found in tanru are also assigned rafsi. If a cmavo embedded in a tanru does not have a rafsi, you may have to paraphrase the tanru in some way.) These rafsi are then attached together by fixed rules that allow the resulting compound to be recognized as a single word and to be broken down in only one way. Some conventions that have been adopted for this are listed at the end of this essay. There are four other complications:
The lujvo must be formed according to Lojban's word-formation rules.
Because of these rules, there is usually more than one rafsi usable for each gismu. The one to be used is simply whichever sounds best to the speaker/writer. There are many valid combinations of the possible rafsi. Any rafsi for a given word is equally valid in place of another, AND ALL MEAN THE SAME THING. There is an optional scoring component to the lujvo-makingalgorithm which attempts to systematically pick the 'best' one; this algorithm tries for short forms and tends to push more vowels into the words to make them easier to say. The Japanese, Chinese, and Polynesian speakers will prefer this; Russians have a different aesthetic, since they are used to saying consonant clusters. But these are not necessarily the criteria you will wish to use. (However, the highest scoring version of a word will be the form chosen to appear in a Lojban dictionary.)
While a tanru is ambiguous, having several possible meanings, a lujvo (one that would be put into the dictionary) has ONE MEANING. Just like gismu, a lujvo is a predicate which encompasses one area of the semantic universe, with one set of sumti places. Hopefully this is the most 'useful' or 'logical' of the possible semantic spaces.
A known source of linguistic drift in Lojban will be as Lojbanic society evolves, and the concept represented by a sequence of rafsi that is most 'useful' or 'logical' changes. At that time, it might bedecided that we want to redefine the lujvo to assume the new meaning; lujvo must not be allowed to retain two meanings. So those that maintain the dictionary will be ever watchful of tanru and lujvo usage to ensure this standard is kept. One should try to be aware of the possibility of prior meanings of a new lujvo, especially if you are writing for 'posterity'. If a lujvo is invented which involves the same tanru as one that is in the dictionary, and is assigned a different meaning (including a different place structure), linguistic drift results. This isn't necessarily bad; something like this happens in every natural language. You communicate quite well in English even though you don't know most words in the dictionary, and in spite of the fact that you use some words in ways not found in the dictionary. Whenever you use a meaning different from the dictionary definition, you risk a reader/listener using the dictionary, finding a different definition, and therefore misunderstanding you. One major reason for having a standard lujvo scoring algorithm is that with several possible rafsi choices to consider, a dictionary is most efficient by putting the definition under the single most preferred form.
You may optionally mark a nonce word that you create without checking a dictionary by preceding it with "za'e". "za'e" simply tells the listener that the word is a nonce word, and may not agree with a dictionary entry for that sequence of rafsi.
The essential nature of human communication is that if the listener understands, then all is well. Let this be the ultimate guideline for choosing meanings and place structures for invented lujvo.
This complication is simple, but is the scariest. Zipf's Law (actually ahypothesis), says that the length of words is inversely proportional to their frequency of usage. The shortest words are those which are used more; the longest ones are used less. The corollary for Lojban is that commonly used concepts will tend to be abbreviated. Speakers will choose the shortest form for frequently expressed ideas that gets their meaning across, even at the cost of accuracy in meaning. In English, we have abbreviations and acronyms and jargon, all of which are words for complex ideas used with high frequency by a group of people. So they shortened them to convey the often-used in-formation more rapidly. The jargon-forming interpretation of Zipf's Law may be a cause of multiple meanings of words in the natural languages, especially of short words. If true, it threatens the Lojban rule that all lujvo must have one meaning.
The Lojbanist thus resigned accepts a complication in lujvo-making: A perfectly good and clear tanru may have to be abbreviated, if the concept it represents likely will be used so often as to cause Zipf's Law to take effect. Thus, given a tanru with grouping markers, abstraction markers, and other cmavo in it to make the tanru syntactically unambiguous, in many cases one drops some of the cmavo to make a shorter (incorrect) tanru, and then uses that one to make the lujvo.
This doesn't lead to ambiguity, as it might seem. A given lujvo still has exactly one meaning and place structure. But now, more than one tanru is competing for the same lujvo. This is not as difficult to accept or allow for as it might seem: more than one meaning for a single tanru was alreadycompeting for the 'right' to be used for the lujvo. Someone has to use judgement in deciding which one meaning is to be chosen over the others.
This judgement will be made on the basis of usage, presumably by some fairly logical criteria. If the lujvo made by a shorter form of tanru is already in use, or is likely to be useful for another meaning, the wordmaker then retains one or more of the cmavo, preferably ones that clearly set this meaning apart from the shorter form meaning that is used or anticipated. In Lojban, therefore, shorter lujvo will be used for a less complicated concept, possibly even over a more frequent word. If two concepts compete for a single rafsi sequence, the simpler concept will take a shorter form, and the more complex concept will have some indication of its more complex nature added into the word structure. It is easier to add a cmavo to clarify the meaning of a more complex term than it is to find a good alternate tanru for the simpler term.
A good lujvo-composer considers the listener, and a good lujvo interpreterremebers the difficulties of lujvo-making. If someone hears a word he doesn't know, decomposes it, and gets a tanru that makes no sense for the context, he knows that the grouping operators may have been dropped out, he may try alternate groupings. Or he may try using the verb form of the concept instead of the first sumti, inserting an abstraction operator if it seems plausible. Plausibility is key to learning new ideas, and evaluating unfamiliar lujvo.