Connecting sumti

The most common connective for sumti is AND. In fact we've already seen this as early as Lesson 7: .i ko'a .e ko'i xanka cmila ("Jyoti and Susan laugh nervously"). Here's another example:

mi ponse pa gerku .e re mlatu
I possess one dog AND two cat
I've got a dog and two cats.

This is actually a contracted way of saying "It is true that I have a dog; it is true that I have two cats," or in Lojban,

mi ponse pa gerku .ije mi ponse re mlatu

Not all English sentences containing and are like this, though. Firstly, sentences like "I had a bath and washed my hair" are structurally different and will be dealt with later on. Secondly, "I visited Ranjeet and Jyoti" is slightly different from "I visited Ranjeet AND I visited Jyoti." In this case, you probably want to say that you visited Ranjeet-and-Jyoti as a unit on one occasion — not that you visited Ranjeet and Jyoti on (potentially) different occasions ("It is true that I visited Ranjit, and it is true that I visited Jyoti.") In this case you don't want .e (which is true but potentially misleading), but joi, which means 'in a mass with'. So what you have is

mi pu vitke la ranjit. joi la djiotis.
I past visit Ranjeet in-a-mass-with Jyoti
I visited Ranjeet and Jyoti (together).

You've seen joi before, too: in Lesson 5, where Marx and Engels wrote The Communist Manifesto as a joint project, rather than individually (la marks. joi la .engels. finti le guntrusi'o selpeicku.) This is just like the difference between le ci gerku and lei ci gerku which we looked at in Lesson 4 — considering the three dogs as individuals, or as a mass. Incidentally, it is not just Lojban which makes this distinction; Turkish, for example, would use ile ('with') rather than ve ('and') for joi here.

We can also use OR here. For example,

mi ba vitke le mi mamta .a le mi tamne
I future visit the me mother OR the me cousin
I'll visit my mother or my cousin.

This leaves open the possibility that I will get round to visiting both of them at some point. If I want to say that that I will visit either my mother or my cousin but not both, I need EOR. For this we use .onai. This is actually a negative IFF, which sounds confusing, but is quite simple and logical. "If and only if I do not visit my cousin, I will visit my mother" logically implies that, if I visit my cousin, I will not visit my mother, and vice versa; so I will visit either my mother or my cousin but not both. So we have

mi ba vitke le mi mamta .onai le mi tamne
I future visit the me mother EOR the me cousin 
I'll visit either my mother or my cousin.

It is probably obvious that .o means IFF, so "I will visit my mother if (and only if) I visit my cousin" would be mi ba vitke le mi mamta .o le mi tamne. If, for some strange reason, I want to use IF and say that I will definitely visit my mother if I visit my cousin, but I may visit her anyway, I need another negative: .anai. But since this is rare in sumti connection, I'll leave that till later.

Finally, there is .u, meaning 'whether or not'. This is not a standard Boolean operator, but I've called it WON for convenience. In this way I can say

mi ba vitke le mi mamta .u le mi tamne
I future visit the me mother WON the me cousin
I'll visit my mother whether or not I visit my cousin.

To sum up:















x1 fancies x2 (cinse 'sex' + nelci 'like')


x1 is a fish of species x2


x1 is made of/contains/is a quantity of juice/nectar from-source/of-type x2


x1 is orange [color adjective]


x1 is a quantity of citrus [fruit/tree, etc.] of species/strain x2


x1 is a potato [an edible tuber] of variety/cultivar x2


x1 is yellow/golden [color adjective]


fry (grasu 'grease' + jukpa 'cook')

Exercise 2

Express the following in Lojban. Don't try to translate the English word for word; work out what the Boolean operator is first, then work from that.

  1. Susan fancies Zhang or Ranjeet, or maybe both of them.

  2. I like fish and chips.

  3. Request (= order) the lemon juice or the orange juice. (Hint: Build expressions for 'lemon' and 'orange' (the fruit) as tanru.)

  4. I want the beer, whether or not I want the curry. (Hint: This is a single bridi, 'want'!)

  5. If I go from Boston to Washington, I'll go all the way to Atlanta. (Hint: This too involves a single bridi.)