Phonology

Each Lojban sound is uniquely assigned to a single letter, or combination of letters. Each letter is defined to have a particular set of possible pronunciations, such that there is no overlap between letter sounds.

Most of the consonants are pronounced exactly as they are most commonly pronounced in English. The following gives English and Lojban examples for these.

Incidentally, for these examples, the Lojban example is a close equivalent of the English example used, showing that some words in Lojban are very similar to their English counterparts. In the pronunciation guides, note the conventions of capitalizing stressed syllables and of separating syllables with commas. These conventions could optionally be used in the Lojban words themselves, but are not necessary.

In the above examples, the consonants in the first table are called unvoiced consonants, because they are spoken without voicing them using the vocal folds. The consonants in the second table are their voiced equivalents.

When a consonant is made by touching the tongue so as to block air passage, it is called a stop (p, b, t, d, k, g). If the blockage is incomplete, and air rubs between the tongue and the roof of the mouth, it is called a fricative (f, v, s, z). For example, k is an unvoiced stop in the back of the mouth. Its unvoiced fricative equivalent is x, which is rarely found in English (the Scottish loch, as in Loch Ness monster, is an example).

Two other fricatives are c and j. c is the unvoiced /sh/ sound that is usually represented by two letters in English. j is its voiced equivalent, rarely occurring alone in English (but see below).

These two fricatives occur frequently in English combined with a stop (giving affricates). Lojban phonology recognizes this, and the /ch/ sound is written tc, while the /j/ sound is written dj.

The other four Lojban consonants are also pronounced as in English. But each has two possible pronunciations. The normal Lojban pronunciation is shown in the first table. In names, borrowings, and a few other situations, however, these consonants can occur in a syllable of their own, with no vowel. In this case they are called syllabic consonants, and are pronounced as in the second table.

Consonants may be found in pairs, or even in triples, in many Lojban words; even longer clusters of consonants, often including at least one syllabic consonant, may be found in Lojbanized names or borrowings. Some of these clusters may appear strange to the English speaker (for example mlatu /MLAH,tu/), but all permitted clusters were chosen so as to be quite pronounceable by most speakers and understandable to most listeners. If you run across a cluster that you simply cannot pronounce because of its unfamiliarity, it is permissible to insert a very short non-Lojban vowel sound between them. The English /i/ as in bit is recommended for English speakers.

The basic Lojban vowels are best described as being similar to the vowels of Spanish and Italian. These languages use pure vowels, whereas English commonly uses vowels that are complexes of two or more pure vowels called diphthongs (2-sounds) or triphthongs (3-sounds). English speakers must work at keeping the sounds pure; a crisp, clipped speech tends to help, along with keeping the lips and tongue tensed (for example by smiling tightly) while speaking.

There are five common vowels (a, e, i, o, u), and one special-purpose vowel (y). English words that are close in pronunciation are given, but few speakers pronounce these words in English with the purity and tension needed in Lojban pronunciation.

The sound represented by y, called 'schwa', is a totally relaxed sound, contrasting with all the other tensed vowels. In this way, the Lojban vowels are maximally separated among possible vowel sounds. The English speaker must be especially careful to ensure that a final unstressed vowel a in a Lojban word is kept tensed, and not relaxed as in the English sofa (compare the equivalent Lojban sfofa /SFO,fah/, not sfofy /SFO,fuh/).

Lojban has diphthongs as well, but these are always represented by the two vowels that combine to form them:

The diphthongs in the second table are found in Lojban only when used as words by themselves, and in Lojbanized names. Those in the first table may be found anywhere.

Any other time these vowel pairs occur together in a single word, they must be kept separate in order to unambiguously distinguish the separate vowels from the diphthongs. The principle has been extended to all Lojban vowels for consistency, and all non-diphthong vowel pairs in a word are separated in print and in sound by an apostrophe ('), representing a short, breathy /h/ sound. (Say Oh hello quickly and without a pause between the words to get an English equivalent, in this case of Lojban o'e. Any voiceless non-Lojban sound may also be used.)

When the vowels occur together, one at the end of a word and the other at the beginning of the next word, the ' is not used to separate them. (Were it used, it would join them into a single word). Instead, a pause is mandatory between the two vowels. The pause may be extremely short (called a glottal stop) as in the English he eats, or may be longer. The pause is mandatory and thus may be inferred without writing it, but it is usually signalled to a reader with a period (.) before the word starting with a vowel.

A pause is also required after any Lojban name, which always ends in a consonant. (A "." is written after the name to mark this, thus distinguishing names from other words without using capitalization.) Every vowel-initial Lojban word is thus preceded by a pause, and such words are usually spelled with a "." at the beginning. There are a small number of other places where pauses are required to separate words. "." may be used to mark the separation in these cases as well.

Lojban words of more than one syllable are stressed on the next-to-last, or penultimate, syllable. (The apostrophe counts as a syllable break: blari'o is stressed as blaRI'o.) Syllables for which the vowel is y are not counted in determining penultimate stress, nor are syllables counted in which the letters l, m, n, or r occur in their syllabic forms, with no other vowel in the same syllable. (Thus, lobypli = LO,by,pli, .uacintn. = .UA,cin,tn., kat,rin. = KAT,r,in.) In Lojbanized names, a speaker may retain a semblance of native pronunciation of the name by stressing a non-penultimate syllable. In this case, capitalization is used to mark the abnormal stress, as in DJOsefin. 'Josephine' in the example above.

It is not mandatory to mark stress and pause in writing in Lojban, except for word separation according to the rules above. There is no mandatory intonation, like the rising tone that always accompanies an English question. Lojban equivalents of English intonations are expressed as spoken (and written) words, and may be adequately communicated even in a monotone voice. Such intonation, and pauses for phrasing, are then totally at the speaker's discretion for ease in speaking or being understood, and carry no meaning of their own.