Getting started with Lojban (alpha)

Abstractions

So far we have only expressed single sentences one at a time. To express more complex things, however, you often need subordinate sentences. Luckily, these are much easier in Lojban than what one would expect.

We will begin with an example to demonstrate this:

I am happy that you are my friend.

Here, the main bridi is "I am happy that X" and the sub-bridi is "you are my friend". Let's look at the definition for the word "happy" in Lojban:

gleki x1 is happy/gay/merry/glad/gleeful about x2 (event/state).

Notice that the second place of gleki can either be an event or a state. This is natural, because one cannot be happy about an object in itself, only about some state the object is in. But alas! Only bridi can express a state or an event, and only sumti can fill the x₂ of gleki!

As you might have guessed, there is a solution. The construct su'u...kei has the function of converting bridi into selbri (similarly to how lo...ku converts selbri into sumti).

su'u generalized abstractor – x₁ is <BRIDI> as a non-specific abstraction of type x₂.

kei end abstraction.

So "X su'u do pendo mi kei" would mean "X is (a non-specific abstraction of) you being my friend". It's usually hard to find good uses of a bridi directly as a selbri. However, since "su'u <BRIDI> kei" is a selbri, one can convert it to a sumti using lo...ku, yielding "lo su'u <BRIDI> kei ku":

Specialized abstractors

In practice, su'u...kei does not see much use. Since su'u...kei is a general abstractor, it will work in all cases – but be careful: if context is not sufficiently clear, the listener may have trouble figuring out precisely what you mean. There are a variety of specialized abstractors, each conveying a specific, more precise meaning than su'u..kei. The two most popular ones are nu...kei and du'u...kei. There are many others, but we will only focus on these two for now.

nu: event/state abstractor

The construct nu...kei treats the bridi in between as an event or state, i.e. something which happens or could happen physically and/or spacially.

nu generalized event abstractor – x₁ is a state/process/achievement/activity of <BRIDI>.

Let's see an example:

As seen in the definition of gleki, the x₂ can be either an event or a state, which means that filling it with "lo nu <BRIDI> kei ku" is appropriate.

Two more examples:

This last example is slightly different, as nu is now being used as a state abstractor. In Lojban, the term "state" generally refers to an event considered as something that is either happening or not happening, with sharp boundaries.

du'u: predication abstractor

The construct du'u...kei treats the bridi in between as a predication.

du'u predication/bridi abstractor – x₁ is the predication of <BRIDI>, as expressed in sentence x₂.

Let's see an example:

As seen in the definition of djuno, the x₂ is a fact, which must be a predication. Notice that "mi djuno lo nu do pendo mi kei ku" would not work, as one can only know facts/predications, not events or states.

One more example:

Note that, in principle, "the house being yellow" could be viewed either as a state (lo nu lo zdani ku pelxu kei ku) or as a predication (lo du'u lo zdani ku pelxu kei ku). However, in the context of ctuca, only a predication makes sense, and hence only du'u is appropriate. But there are also situations in which more than one abstractor may be valid in the same sentence – yielding subtle differences in meaning or emphasis.

Finally, note that the sentence above asserts "the person is teaching", but does not assert the nested proposition "the house is yellow". It could be that the house is actually blue, and the person is teaching something untruthful. On the other hand, placing lo nu lo zdani ku pelxu kei ku anywhere within a bridi, without additional context, would generally imply, at least implicitly, that the house is (or was or will be) yellow. (More precisely, it would imply that there exists at least one event of the house being yellow.)

se du'u: indirect quotation

If you look carefully at the definition of du'u, you will notice that, besides the abstract predication itself (x₁), it also has a second sumti place for the text of the predication (x₂). Hence, "X se du'u do pendo mi kei" means "X is the text corresponding to the predication of you being my friend".

This is often used for indirect quotation. For a concrete example, let's use the word cusku:

cusku x₁ (agent) expresses/says x₂ (sedu'u/text/lu'e concept) for audience x₃ via expressive medium x₄.

As se du'u is recognized as an indirect quotation, imagine quoting the text behind the predication. If it seems confusing, try to substitute "that" to show the indirectness of the quote. Also notice how do cusku lo se du'u do pendo mi kei ku – "You say that you are my friend" is different from "You say 'you are my friend'" (which we are yet to learn how to express in Lojban).

Final example:

Choosing the appropriate abstractor

When should you use one abstractor instead of the others?

More often than not, the definition of the gismu will include the explicit abstraction of a place. If not, ask yourself the following question: "Do I wish to make the place an event, a state, a predicate, or the text behind the predicate?"

Exercises

It's now time for you to attempt a few more translations. You will need the following new word:

nupre x1 (agent) promises/commits/assures/threatens x2 (event/state) to x3 [beneficiary/victim].

Translate the following sentences from Lojban into English:

Sentence	Possible translation
do nupre lo nu tavla mi kei ku	You promised that (you) would talk to me.
do cusku lo sedu'u mi nelci lo mlatu ku kei ku	You said that I like cats.
mi gleki lo nu lo zdani ku pelxu kei ku	I am happy that the house is yellow.
xu do djuno lo du'u lo prenu ku ctuca lo gerku ku kei ku	Did you know that people teach dogs?

Now, translate the following sentences from English into Lojban:

Sentence	Possible translation
Did you say that the cat is beautiful?	xu do cusku lo sedu'u lo mlatu ku melbi kei ku
I am glad that you taught me.	mi gleki lo nu do ctuca mi kei ku
What do you know that I did?	do djuno lo du'u mi mo kei ku
What did you promise that you would donate to me?	do nupre lo nu do dunda ma mi kei ku [or] do nupre lo nu dunda ma mi kei ku

Final remarks

It may be helpful to memorize "se du'u" as a single construct, which indicates that what follows is an indirect quotation, instead of always mentally decomposing it into se + du'u. Indeed, some people even write "lo sedu'u" instead of "lo se du'u". This is allowed, since "se" and "du'u" are cmavo ("structure words") and in Lojban it is valid to concatenate arbitrary sequences of cmavo together, without spaces, as if they were a single word. That is why "se du'u" is commonly seen as "sedu'u", and "lo nu/du'u/se du'u" is sometimes seen as "lonu/lodu'u/losedu'u". We will learn more about the morphological classes later.

Practice

As usual, before proceeding to the next lesson, get some practice with interactive exercises – smash that "Practice" button below!

Beware that exercises loop indefinitely, so feel free to stop once you feel you've had enough. And be sure to revisit exercises on different days, to benefit from the spacing effect.