Not every sound change works on just consonants or just vowels. Some can transmute one into the other. Others affect entire syllables or words. A few work on a different level entirely. So, we’ll finish this series by looking at these “miscellaneous” types of evolution.
Tones
Tones have to come from somewhere. One of the ways they can appear (tonogenesis) is through the loss of consonants preceding or following a vowel. A voiced consonant, for instance, can cause the vowel after it to be spoken at a lower pitch. If those consonant go away, the change in pitch can remain: a low tone. As another example, a number of consonant elisions led to the tonal system of Chinese, along with its restrictive syllable structure.
Once a language has tone, it becomes a target for evolution. Tones can change, merge, split, and disappear, exactly as phonemes. Unstressed syllables may develop a neutral tone, which might get reanalyzed as one of the existing tones. Sequences of tones can affect each other, as well, a complex process called tone sandhi.
Like any other part of language, tone is subject to the same forces that drive all sound change, which can be summed up as human laziness. More on that later.
Sandhi
The term sandhi comes from Sanskrit; roughly speaking, it means “joining”. In modern linguistics, it’s a catch-all term used for any kind of sound change that crosses the boundary between morphemes. The “linking” R in some English dialects is a kind of sandhi, and so is the use of the article “an” before vowels. Romance languages show a couple more instances of the process: Spanish de el → del; Italian della → dell’; the heavy use of liaison in French.
When sandhi becomes systematic, it can create new words, like Spanish del and al. These, of course, can then be changed by any other sound change. And it’s not limited to vowels. Consonants can also be affected by sandhi. The most common expression of this is anticipatory voicing across word boundaries, but other types of assimilation are equally valid.
Epenthesis
Epenthesis is the adding of a sound, the opposite of elision. It’s another way of breaking up a cluster that violates a language’s phonological rules or aesthetic sensibilities. Some epenthesis is a kind of sandhi, like English “an”, and the diaresis discussed last week is another form. Those aren’t the only possibilities, though.
An epenthetic vowel can be inserted between two consonants, and this will usually be a neutral vowel, whatever the language considers that to be. Schwa (/ə/) is a common choice, but /e/, /a/, and /o/ also pop up. /i/ and /u/, however, are usually too strong.
Similarly, strings of vowels may be broken up by epenthetic consonants. Again, something weak and unassuming is needed, something like /r/, /n/, /l/, /h/, or /ʔ/. /w/ and /j/ can be used as glides, as we have seen, but they’ll tend to be used only when they can relate to one of the vowels.
Another option for consonant clusters is an epenthetic consonant, one that bridges the gap between the two. Greek, for example, shows a sound change /mr/ → /mbr/, as seen in words like “ambrosia”. Many speakers of English insert epenthetic consonants like this all over, without even knowing it, like the [p] in “something”. (If this became phonemic, it would be essentially the same thing that happened to Greek.)
Haplology
Two syllables that are fairly close in sound may not stay together for very long. Haplology is a sound change that involves the deletion of one syllable of such a pair. It can be either one, and there’s no standard for how “close” two syllables need to be to trigger the change. English examples include the common pronunciations of “probably” and “February”, and others aren’t hard to find. (In another one of those linguistic oddities, “haplology” itself can fall victim to this, becoming “haplogy”.)
Applying the rules
Although there are plenty of other sound changes out there—again, I refer you to Index Diachronica for more—we have gathered enough over the last three posts to start looking at how to apply them to a conlang. There are plenty of programs out there that can do this for you, but it helps to know the rules. These aren’t set in stone, mind you, but you should have a good reason for breaking them. (That reason would probably lead to more conlanging, so I’m not complaining.)
First, evolutionary sound changes are regular. They’ll almost always happen when the right conditions are met. If you’ve got devoicing of final stops, as in German, then essentially every final stop is going to get devoiced. Sure, there may be exceptions, but those exceptions can be explained. Maybe those words appeared in their current forms after the sound change.
Second, remember that sound changes don’t care. This is a subset of regularity, but it bears repeating. A sound change will affect a word no matter what that word’s history. A particular evolutionary condition may be met because of an earlier sound change, but later changes won’t know that. They’ll only “see” a word ripe for alteration.
Third, sound changes operate on a lower level. They’re “below” grammar and, as such, aren’t affected by it. But this means that grammatical ambiguity can arise, as when sounds of case endings are merged or dropped. (This one happened in both English and the Romance languages.) Speakers will then need to find ways of clearing things up, leading to innovations on the grammar side of things.
Fourth, sound change stems from laziness, a desire to minimize the effort required in speaking and conveying our thoughts. Weak sounds disappear, dissimilar sounds merge, and it’s all because we, as a whole, know we can get away with it. As long as there’s enough left to get the message across, all else is simply extraneous baggage. And that’s what’s most likely to change.
Finally, evolution is unceasing. When it comes to language, the only constant is change. Even our best efforts at writing and education and language academies can’t stop sound change. There will always be differences in speech. Those will form dialects, and then those may split into new, mutually unintelligible languages.