The following cmavo is discussed in this section:

The standard order of Lojban tanru, whereby the modifier precedes what it modifies, is very natural to English-speakers: we talk of “blue houses”, not of “houses blue”. In other languages, however, such matters are differently arranged, and Lojban supports this reverse order (tertau before seltau) by inserting the particle co. Example 5.76 and Example 5.77 mean exactly the same thing:

This change is called “tanru inversion”. In tanru inversion, the element before co (zdani in Example 5.77) is the tertau, and the element following co (blanu) in Example 5.77) is the seltau.

The meaning, and more specifically, the place structure, of a tanru is not affected by inversion: the place structure of zdani co blanu is still that of zdani. However, the existence of inversion in a selbri has a very special effect on any sumti which follow that selbri. Instead of being interpreted as filling places of the selbri, they actually fill the places (starting with x₂) of the seltau. In Section 5.7, we saw how to fill interior places with be … bei … be'o, and in fact Example 5.78 and Example 5.79 have the same meaning:

Example 5.79 is a less deeply nested construction, requiring fewer cmavo. As a result it is probably easier to understand.

Note that in Lojban “trying to go” is expressed using troci as the tertau. The reason is that “trying to go” is a “going type of trying”, not a “trying type of going”. The trying is more fundamental than the going – if the trying fails, we may not have a going at all.

Any sumti which precede a selbri with an inverted tanru fill the places of the selbri (i.e., the places of the tertau) in the ordinary way. In Example 5.79, mi fills the x₁ place of troci co klama, which is the x₁ place of troci. The other places of the selbri remain unfilled. The trailing sumti le zarci and le zdani do not occupy selbri places, despite appearances.

As a result, the regular mechanisms (involving the vo'a and the go'a-series, explained in Section 7.6 and Section 7.8) for referring to individual sumti of a bridi cannot refer to any of the trailing places of Example 5.79, because they are not really “sumti of the bridi” at all.

When inverting a more complex tanru, it is possible to invert it only at the most general modifier-modified pair. The only possible inversion of Example 5.19, for instance, is:

Note that the bo of Example 5.19 is optional in Example 5.80, because co groups more loosely than any other cmavo used in tanru, including none at all. Not even ke … ke'e parentheses can encompass a co:

In Example 5.81, the ke'e is automatically inserted before the co rather than at its usual place at the end of the selbri. As a result, there is a simple and mechanical rule for removing co from any selbri: change “A co B” to “ke B ke'e A”. (At the same time, any sumti following the selbri must be transformed into be … bei … be'o form and attached following B.) Therefore,

means the same as:

Multiple co cmavo can appear within a selbri, indicating multiple inversions: a right-grouping rule is employed, as for bo. The above rule can be applied to interpret such selbri, but all co cmavo must be removed simultaneously:

becomes formally

which by the left-grouping rule is simply

As stated above, the selbri places, other than the first, of

cannot be filled by placing sumti after the selbri, because any sumti in that position fill the places of sutra, the seltau. However, the tertau places (which means in effect the selbri places) can be filled with be: