Chapter 17: As Easy As A-B-C? The Lojban Letteral System And Its Uses
3. Upper and lower cases
Lojban doesn't use lower-case (small) letters and upper-case (capital) letters in the same way that English does; sentences do not begin with an upper-case letter, nor do names. However, upper-case letters are used in Lojban to mark irregular stress within names, thus:
✥3.1 .iVAN. the name “Ivan” in Russian/Slavic pronunciation.
It would require far too many cmavo to assign one for each upper-case and one for each lower-case lerfu, so instead we have two special cmavo “ga'e” and “to'a” representing upper case and lower case respectively. They belong to the same selma'o as the basic lerfu words, namely BY, and they may be freely interspersed with them.
The effect of “ga'e” is to change the interpretation of all lerfu words following it to be the upper-case version of the lerfu. An occurrence of “to'a” causes the interpretation to revert to lower case. Thus, “ga'e .abu” means not “a” but “A”, and Ivan's name may be spelled out thus:
✥3.2 .ibu ga'e vy. .abu ny. to'a i [upper] V A N [lower]
The cmavo and compound cmavo of this type will be called “shift words”.
How long does a shift word last? Theoretically, until the next shift word that contradicts it or until the end of text. In practice, it is common to presume that a shift word is only in effect until the next word other than a lerfu word is found.
It is often convenient to shift just a single letter to upper case. The cmavo “tau”, of selma'o LAU, is useful for the purpose. A LAU cmavo must always be immediately followed by a BY cmavo or its equivalent: the combination is grammatically equivalent to a single BY. (See c17-§14 for details.)
A likely use of “tau” is in the internationally standardized symbols for the chemical elements. Each element is represented using either a single upper-case lerfu or one upper-case lerfu followed by one lower-case lerfu:
✥3.3 tau sy. [single shift] S S (chemical symbol for sulfur)
✥3.4 tau sy. .ibu [single shift] S i Si (chemical symbol for silicon)
If a shift to upper-case is in effect when “tau” appears, it shifts the next lerfu word only to lower case, reversing its usual effect.