Syllabification

[Emma May Smith]

In very broad terms, the more vowels you assign to characters the more pronounceable a text becomes. This is because vowels form the nucleus of syllables* and in most languages** vowel-only syllables are valid***. So long as you're happy with every vowel representing a syllable, even a string like eiuoaueioa can be pronounced.

The problems stack up as the ratio of consonants to vowels increases. As consonants are not typically the nuclei of syllables, any string of sounds must be split up into syllables according to the vowels available. Syllable parsing is often contestable, and different people may assign consonants to the end or beginning of neighbouring syllables depending on their viewpoint. But as the ratio of consonants increases so too does the number of sequential consonants occurring either side of vowel. These are consonant clusters.

Some languages--such as English--deal pretty well with consonant clusters, allowing three or even four consonants in a row: strengths is a canonical example, with three beginning consonants and four**** ending consonants around a lone vowel. Most languages don't allow such complex syllables to exist, with a word like twin being more typical of the most complex syllables allowed.

But the important thing is that no matter how complex syllables can be, they must adhere to a rule known as the sonority sequencing principle. Broadly, all sounds have a characteristic known as sonority, that vowels have the highest sonority of all sounds, that syllables should have a single peak of sonority, and that sonority within a syllable should increase and decrease regularly to and from that peak. In short, sonority is highest nearest the vowel.

So, if I tell you that /p/ has a lower sonority than /l/, which naturally has a lower sonority than the vowel /a/, we can compose valid syllables from these three sounds: /pal/, /lap/, /alp/, and /pla/; and the invalid /lpa/ and /apl/. For the first two sonority goes up and then down, with the peak at the vowel; for the next two sonority starts high and falls or starts low and climbs, but again with the vowel being the high point; but for the last two sonority drops then rises, with both /a/ and /l/ being peaks either side of /p/.

The principle is not hard and fast but it is a good guide. It is also a universal rule, governed by how humans speak rather than any given language. We internalize it as we learn to speak and can replicate it even without knowing of its existence. Thus when Rene and Landini made EVA pronounceable they were implicitly seeking out the sonority curve and applying sounds to it they knew would fit. The assignment of EVA characters is neither random nor, importantly, meaningless. Moreover, as the number of different characters within a text increases the only two options available to make that text pronounceable is either to make more of the characters vowels or to assign characters values that increasingly approximate the sonority hierarchy.


* Consonants can form the nucleus of syllables, but this is less common and typically marginal in any given language.
** A few languages don't permit vowel-only syllables. The Voynich candidate-darling Hawaiian is supposedly one, but I think this is wrong.
*** That is, phonologically valid. Such words can be pronounced even if meaningless.
**** Even though written as three sounds: /ng th s/; it is often pronounced with an inserted /k/: /ng k th s/.