I’m not sure how this phonological feature has so far escaped a TwwEh post, especially considering it’s something that I deal with every day when working on Yolmo!

English speakers use pitch, but we use it at the ‘supra-segmental’ level, for things such as making questions but raising the pitch at the end of a sentence. Tone is where you use pitch quality of to make a lexical or grammatical distinction.

Tone is something that English and most Indo-European language speakers think of as exotic because it’s not a prominent feature of their language family, but tone is relatively common world-wide (and in Indo-European there’s some tonal distinctions in Swedish and Norwegian). Of the 527 languages surveyed on WALS 220 have tone.

So what you end up with are words that have exactly the same consonants and vowels but the change in pitch makes completely different words. To give you an example from Mandarin Chinese because it’s one of the most well known tone languages, and because it has an impressive-looking five way contrast:

1. mā “mom”
2. má “hemp”
3. mǎ “horse”
4. mà “scold”
5. ma (an interrogative particle)

The only thing to distinguish these words is the way the register rises, falls or stays level.

But not all tone languages are the same, there are lots of different ways tone can be expressed. Some languages like Chinese use the pitch height, but more importantly it also uses the contour of the pitch as well - it’s relatively easy to hear the rise or fall of these tones in context. Other languages, like Yolmo, make a different between high and low tone by the height of the pitch. This is fine, but often means that in one context a high tone might be lower than a low tone in another context which can make it hard to tune it. For some of these languages the high or low tone might correlate with something like creaky voice or certain initial consonants to make identification easier. For example, Yolmo low tone correlates with breathy voice and if a stop is affricated the tone will always be high.

Some languages have tone marked on the initial syllable of a word, while other languages mark tone on each syllable. The number of tonal distinctions also vary - as you saw above Mandarin has five tones while Yolmo only has two. Pitch accent tend to have more tone; Cantonese has seven tones, and there are possibly languages with more.

On a geeky level I like tone because of its ability to create more information density. Even if you only have a two tone system you automatically double the number of single syllable items you have. A friend once told me he read a paper that there is a higher density of people with ‘perfect pitch’ in languages with pitch heigh, but I didn’t get a reference. If anyone knows this study, do share!