## 19.13. Erasure: SI, SA, SU

The following cmavo are discussed in this section:

 si SI erase word sa SA erase phrase su SU erase discourse

The cmavo si (of selma'o SI) is a metalinguistic operator that erases the preceding word, as if it had never been spoken:

Example 19.76.

 ti gerku si mlatu This is-a-dog, er, is-a-cat.

means the same thing as ti mlatu. Multiple si cmavo in succession erase the appropriate number of words:

Example 19.77.

 ta blanu zdani si si xekri zdani That is-a-blue house, er, er, is-a-black house.

In order to erase the word zo, it is necessary to use two si cmavo in a row:

Example 19.78.

 zo .bab. cmene zo si si la .bab. The-word “Bob” is-the-name-of the word si, er, Bob.

The first use of si does not erase anything, but completes the zo quotation. Then, a single si is sufficient to erase the quotation (cmavo after a zo quote treat it as if it were a single word).

Incorrect names can likewise cause trouble with si:

Example 19.79.

 mi tavla fo la .esperanto I talk in-language that-named and-speranto,
 si si .esperanton. er, er, Esperanto.

The Lojbanized spelling .esperanto breaks up, as a consequence of the Lojban morphology rules (see Chapter 19) into two Lojban words, the cmavo e and the undefined lujvo speranto. Therefore, two si cmavo are needed to erase them. Of course, .e speranto is not grammatical after la, but recognition of si is done before grammatical analysis.

Similarly messy is the result of an incorrect zoi:

Example 19.80.

 mi cusku zoi fy. fy. si zo .djan. I say [foreign] [quote] [unquote], er, “John” .

In Example 19.80, the first fy is taken to be the delimiting word. The delimiting word must first be repeated to end the quotation. For purposes of si erasure, the entire ZOI structure is taken to be a word, so a single si cmavo is needed to erase it. Similarly, a stray lo'u quotation mark must be erased with le'u si, by completing the quotation and then erasing it with a si cmavo.

As the above examples plainly show, precise erasures with si can be hard to get right. Therefore, the cmavo sa (of selma'o SA) is provided for erasing more than one word. The cmavo following sa should be the starting marker of some grammatical construct. The effect of the sa is to erase back to and including the last starting marker of the same kind. For example:

Example 19.81.

 mi viska la sa .i mi cusku zo .djan. I see that-named ... I say the-word “John” .

Since the word following sa is i, the sentence separator, its effect is to erase the preceding sentence. So Example 19.81 is equivalent to:

Example 19.82.

mi cusku zo .djan.

Another example, erasing a partial description rather than a partial sentence:

Example 19.83.

 mi viska lo blanu .zdan. sa lo xekri zdani I see the blue hou ... the black house.

In Example 19.83, lo blanu .zdan. is ungrammatical, but clearly reflects the speaker's original intention to say lo blanu zdani. However, the zdani was cut off before the end and changed into a name. The entire ungrammatical le construct is erased and replaced by lo xekri zdani.

The cmavo su (of selma'o SU) is yet another metalinguistic operator that erases the entire text, up to the beginning of the last paragraph, lu quote, TO parenthesis, or tu'e grouping.