3.3 The Special Lojban Characters
The Lojban sounds must be clearly pronounced so that they are not mistaken for each other. Voicing and placement of the tongue are the key factors in correct pronunciation, but other subtle differences will develop between consonants in a Lojban-speaking community. At this point these are the only mandatory rules on the range of sounds.
Note in particular that Lojban vowels can be pronounced with either rounded or unrounded lips; typically o and u are rounded and the others are not, as in English, but this is not a requirement; some people round y as well. Lojban consonants can be aspirated or unaspirated. Palatalizing of consonants, as found in Russian and other languages, is not generally acceptable in pronunciation, though a following i may cause it.
The sounds represented by the letters c, g, j, s, and x require special attention for speakers of English, either because they are ambiguous in the orthography of English (c, g, s), or because they are strikingly different in Lojban (c, j, x). The English “c” represents three different sounds, [k] in “cat” and [s] in “cent”, as well as the [ʃ] of “ocean”. Similarly, English “g” can represent [ɡ] as in “go”, [dʒ] as in “gentle”, and [ʒ] as in the second "g" in “garage” (in some pronunciations). English “s” can be either [s] as in “cats”, [z] as in “cards”, [ʃ] as in “tension”, or [ʒ] as in “measure”. The sound of Lojban x doesn't appear in most English dialects at all.
There are two common English sounds that are found in Lojban but are not Lojban consonants: the “ch” of “church” and the “j” of “judge”. In Lojban, these are considered two consonant sounds spoken together without an intervening vowel sound, and so are represented in Lojban by the two separate consonants: tc (IPA [tʃ]) and dj (IPA [dʒ]). In general, whether a complex sound is considered one sound or two depends on the language: Russian views “ts” as a single sound, whereas English, French, and Lojban consider it to be a consonant cluster.
3.3 The Special Lojban Characters
The apostrophe, period, and comma need special attention. They are all used as indicators of a division between syllables, but each has a different pronunciation, and each is used for different reasons:
The apostrophe represents a phoneme similar to a short, breathy English “h”, (IPA [h]). The letter “h” is not used to represent this sound for two reasons: primarily in order to simplify explanations of the morphology, but also because the sound is very common, and the apostrophe is a visually lightweight representation of it. The apostrophe sound is a consonant in nature, but is not treated as either a consonant or a vowel for purposes of Lojban morphology (word-formation), which is explained in Chapter 4 (p. 49). In addition, the apostrophe visually parallels the comma and the period, which are also used (in different ways) to separate syllables.
The apostrophe is included in Lojban only to enable a smooth transition between vowels, while joining the vowels within a single word. In fact, one way to think of the apostrophe is as representing an unvoiced vowel glide.
As a permitted variant, any unvoiced fricative other than those already used in Lojban may be used to render the apostrophe: IPA [θ] is one possibility. The convenience of the listener should be regarded as paramount in deciding to use a substitute for [h].
The period represents a mandatory pause, with no specified length; a glottal stop (IPA [ʔ]) is considered a pause of shortest length. A pause (or glottal stop) may appear between any two words, and in certain cases – explained in detail in Section 4.9 (p. 66) – must occur. In particular, a word beginning with a vowel is always preceded by a pause, and a word ending in a consonant is always followed by a pause.
Technically, the period is an optional reminder to the reader of a mandatory pause that is dictated by the rules of the language; because these rules are unambiguous, a missing period can be inferred from otherwise correct text. Periods are included only as an aid to the reader.
A period also may be found apparently embedded in a word. When this occurs, such a written string is not one word but two, written together to indicate that the writer intends a unitary meaning for the compound. It is not really necessary to use a space between words if a period appears.
The comma is used to indicate a syllable break within a word, generally one that is not obvious to the reader. Such a comma is written to separate syllables, but indicates that there must be no pause between them, in contrast to the period. Between two vowels, a comma indicates that some type of
