# Lojban Wave Lessons/20

 Lojban Wave Lessons: Foreword | ← Lesson 19 | Lesson 20 | Lesson 21 →

## Lesson 20: bo, ke, co, and more cuteness

Say you're an important American buyer of computers. How do you express this? For constructs like these, tanru are ideal: mi vajni merko skami te vecnu. No wait, that's not right. Tanru are grouped from left to right, so this tanru is understood: ((vajni merko) skami) te vecnu, a buyer of computers for important Americans. You can't change the order of the selbri to get a useful tanru. Neither can this be solved with logical connectives, which you will first learn about later anyway. The only way to make a fitting tanru is to force the selbri to group differently.

To bind two selbri close together in a tanru, the word bo can be placed between them: mi vajni bo merko skami bo te vecnu is read mi (vajni bo merko) (skami bo te vecnu), which is useful in this context. If bo is placed between several selbri in a row, they are grouped from right to left instead of the usual left to right: mi vajni merko bo skami bo te vecnu is read vajni (merko bo (skami bo te vecnu)) an important (American computer-buyer), which is even more appropriate in the situation.

bo = Binds two selbri together strongly.

How would you say That's a tasty yellow apple?

kukte = x1 is tasty for x2

Answer: ti kukte pelxu bo plise

What about That's a big, tasty yellow apple?

Answer: ti barda kukte bo pelxu bo plise

Another approach to this is to use the words ke…ke'e. These can be considered as equivalent to the parenthesises used in the paragraph above. ke begins strong selbri grouping, ke'e ends it.

ke = begin strong selbri grouping.
ke'e = end strong selbri grouping.

The strength of the binding is the same as that of bo. Therefore, mi vajni merko bo skami bo te vecnu can be written mi vajni ke merko ke skami te vecnu {ke'e} {ke'e}.

How could you say I'm a German seller of yellow homes?

Answer: mi dotco ke pelxu zdani vecnu

While we're at messing with the ordinary tanru structure, there is another word worth paying attention to. If I want to say that I'm a professional translator, I could say mi fanva se jibri.

jibri = x1 is a job of x2
dotybau = x1 is German used by x2 to say x3
glibau = x1 is English used by x2 to say x3

If I wanted to say that I'm a professional translater from English to German, I'd have to mess around with be and bei: mi fanva be le dotybau bei le glibau be'o se jibri, and the fact that it was a tanru could quickly be lost in speech due to the complicated structure of the sentence. Here, we can use the word co. it inverts the tanru, making the rightmost selbri modify the leftmost instead of the other way around:

mi se jibri co fanva le dotybau le glibau is the same bridi as the previous Lojban one, but much more easy to understand. Notice that any sumti before the tanru fills se jibri, while any following it only fills the modifying selbri: fanva.

co = Invert tanru. Any previous sumti fill the modified, any following fill the modifier.

The strength by which two selbri are bound together with co is very weak – even weaker than normal tanru grouping without any grouping words. This makes sure that, in a co-construct, the leftmost selbri is always the selbri being modified, and the rightmost always modifies, even if any of those parts are tanru. This makes a co-construct easy to parse:

ti pelxu plise co kukte is read ti (pelxu plise) co kukte, which is the same as ti kukte pelxu bo plise. This also means that a ke…ke'e cannot encompass a co.

The cmavo of the selma'o GIhA, the bridi-tail afterthought logical connectives, however, binds even looser than co. This is in order to totally avoid confusion about which selbri binds to which in a GIhA-construct. The answer is simple: The GIhA never emcompasses any selbri-groups.

How can you express I am an important American buyer of computers using a co?

Answer: mi skami te vecnu co vajni merko

If it's of any use, this is the list of different kind of selbri groupers ranked by strength:

1. bo and ke..ke'e
2. logical connectives other than bridi-tail afterthought logical connectives (explained in lesson twenty-five)
3. no grouping words
4. co
5. bridi-tail afterthought logical connectives (also in lesson twenty-five)

The rest of this lesson will not be on selbri grouping, but much like lesson seventeen mention assorted words, which can be of use.

bo has another use, which seems separate from selbri grouping: It can also bind a sumtcita to an entire bridi, so that the content of the sumtcita is not a sumti, but the following bridi. This is best explained with an example.

xebni = x1 hates x2

mi darxi do .i mu'i bo mi do xebniI hit you, with motivation that I hate you. Here the bo binds mu'i to the following bridi.

This is where the technical difference between tense sumtcita and other sumtcita is relevant. You see, when binding a normal sumtcita to a bridi with bo, it means that the following bridi somehow fits into the sumti place of the sumtcita. For the reason of God Knows Why, binding one of the words ba or pu to a bridi has the exact opposite effect. For example, in the bridi mi darxi do .i ba bo do cinjikca, one would assume that the second bridi is somehow filled into the sumti place of ba, meaning that the bridi first uttered took place in the future of the second bridi. That's not the case, however, and the correct translation of that utterance would be "I hit you. Afterwards, you flirt". This weird rule is actually one of the main obstacles to a unification of all sumtcita into one single word class. Another difference is that tense-sumtcita can be elided, even though they apply. This rule makes more sense, since we often can assume bridi is placed in a time and space, but we can't assume that the sumtcita of BAI applies.

The unofficial word me'oi is equivalent to me la'e zo'oi, which means that it converts the content of the next word into a selbri. It is used to invent brivla on the fly: mi ca zgana la me'oi X-files for I now watch X-files. Like zo'oi and la'oi, it doesn't allow space, periods (or pauses in speech) inside.

The word gi is strage kind of bridi separator, analogous to .i, but to my knowledge, it is used in only two different kinds of constructs: Most often with logical connectives, explained in lesson twenty-five, but also with sumtcita. With sumtcita it creates a useful, but hardly seen, construct:

mu'i gi BRIDI-1 gi BRIDI-2, which is equivalent to BRIDI-2 .i mu'i bo BRIDI-1. Therefore, the example above, which explained why I hit you, can be written mu'i gi mi xebni do gi mi darxi do, or to preserve the same order as the original sentence, we can convert mu'i with se: se mu'i gi mi darxi do gi mi xebni do.

It is in examples like this that gi really can show its versatility. It does not just separate two bridi like .i does, but can also separate two constructs within a bridi, making all constructs outside the scope of gi apply to both bridi, as this example demonstrates:

cinba = x1 kisses x2 at locus x3

mi ge prami do gi cinba do leaves mi outside the construct, making it apply to both bridi. This can also be done with do, which is also present in broth bridi: mi ge prami gi cinba vau do. Note that vau is needed to make do appear outside the second bridi.

Thus, we can write the original sentence shorter: mi mu'i gi xebni gi darxi vau do, or, to omit even the vau, we can write it even shorter and more elegantly: mi do mu'i gi xebni gi darxi

 Lojban Wave Lessons: Foreword | ← Lesson 19 | Lesson 20 | Lesson 21 →