ConLing - What is vowel harmony?

There come a few times when studying language when you run across something too bizarrely counterintuitive to dream up - to me, vocalic harmony falls squarely in that category. If I didn't know it existed, I'd probably consider it impossible, but there it is, sitting squarely in the middle of Turkish, Igbo, Finnish, and even some dialects of Spanish. But what exactly is it?

Vocalic harmony is when consonant notes are sung simultaneously. jk, that's vocal harmony (wow! vocal, consonant, singing and linguistics get their terminological wires crossed a lot!) This picture was on the Wikipedia page about vocal harmony so, uh... here. It's more entertaining that any of the pictures on the vowel harmony page.

In my post on allophony, I mentioned assimilation, the phenomenon of nearby sounds becoming more alike, usually by sharing an articulatory feature. Assimilation most commonly happens over short distances, typically adjacent segments, but sometimes sounds freak out and decide they have to agree with even far away sounds, extending their assimilatory sensitivites across a whole word - harmony! In languages with harmonic systems, all sounds of a particular type within a given word live in concordant coexistence with one another, usually separating into multiple sets based on a certain feature and only allowing items from one set in each word.

ConLing - How does allophony work?

Those of us who construct languages have probably seen it before - someone new to the art posts up their newly created phonology to reddit or a bulletin board, and... it's a list. If you hop on Wikipedia or read an academic description of a natural language page down to the section on phonology, it's typically a little bit longer. What gives?

If you're reading the phonology section of the Wikipedia article on Greenlandic, it starts with some lists - vowels, consonants, syllable shapes - but then it starts in on several paragraphs full of rules and sound changes. This is what was missing from the forum post! But maybe new makers of languages are just visible examples of a certain conception we have about the way we speak. It's easy to notice the fact that languages all contain distinct "sounds" (which is to say, phones), but words of course aren't just lawless noise sequences. In early infancy, the rules our mother tongue applies to our native language is irreversibly wired into our brain, so anyone can be forgiven for being blind to them, but the truth is that every word in every language has been run through a phonological filter - allophony.