Consider the example:
9.1) mi tavla bau la lojban. bai tu'a la frank.
I speak in-language Lojban with-compeller some-act-by Frank.
I speak in Lojban, under compulsion by Frank.
Example 9.1 has two modal sumti, using the modals “bau” and “bai”. Suppose we wanted to specify the language explicitly but be vague about who’s doing the compelling. We can simplify Example 9.1 to:
9.2) mi tavla bau la lojban. bai [ku].
I speak in-language Lojban under-compulsion.
In Example 9.2, the elidable terminator “ku” has taken the place of the sumti which would normally follow “bai”. Alternatively, we could specify the one who compels but keep the language vague:
9.3) mi tavla bau [ku] bai tu'a la frank.
I speak in-some-language under-compulsion-by some-act-by Frank.
We are also free to move the modal-plus-“ku” around the bridi:
9.4) bau [ku] bai ku mi tavla
In-some-language under-compulsion I speak.
An alternative to using “ku” is to place the modal cmavo right before the selbri, following the “cu” which often appears there. When a modal is present, the “cu” is almost never necessary.
9.5) mi bai tavla bau la lojban.
I compelledly speak in-language Lojban.
In this use, the modal is like a tanru modifier semantically, although grammatically it is quite distinct. Example 9.5 is very similar in meaning to:
9.6) mi se bapli tavla bau la lojban.
I compelledly-speak in-language Lojban.
The “se” conversion is needed because “bapli tavla” would be a “compeller type of speaker” rather than a “compelled (by someone) type of speaker”, which is what a “bai tavla” is.
If the modal preceding a selbri is constructed using “fi'o”, then “fe'u” is required to prevent the main selbri and the modal selbri from colliding:
9.7) mi fi'o kanla fe'u viska do
I with-eye see you.
I see you with my eye(s).
There are two other uses of modals. A modal can be attached to a pair of bridi-tails that have already been connected by a logical, non-logical, or modal connection (see Chapter 14 for more on logical and non-logical connections):
9.8) mi bai ke ge klama le zarci gi cadzu le bisli [ke'e]
I under-compulsion (both go to-the market and walk on-the ice).
Under compulsion, I both go to the market and walk on the ice.
Here the “bai” is spread over both “klama le zarci” and “cadzu le bisli”, and the “ge ... gi” represents the logical connection “both-and” between the two.
Similarly, a modal can be attached to multiple sentences that have been combined with “tu'e” and “tu'u”, which are explained in more detail in Chapter 19:
9.9) bai tu'e mi klama le zarci .i mi cadzu le bisli [tu'u]
Under-compulsion [start] I go to-the market. I walk on-the ice [end].
means the same thing as Example 9.8.
Note: Either BAI modals or “fi'o”-plus-selbri modals may correctly be used in any of the constructions discussed in this section.