Njaama Tone Sandhi
YEEEEEEEEEEEEEEEEEEHAAAAAAAAAAAAA! Door's open, boys! Anything goes now!
By that I, of course, mean that Njaama no longer is a perfect (i.e., unrealistic) tone language. I wanted to make it so that contour tones were disallowed, as were tone melodies of greater than two tones, so I just changed every offending tone, but alas! That can be no more. For in this great wide world of ours there's a thing called downstep, and poor Njaama has fallen victim to the beast. Yes, if Esperanto were a tone language, it might've acted like the old Njaama, but (thankfully?) it is not. Now, in this world with a brand new Njaama, tone has become slightly more complex (just slightly). Here's how it goes:
What frightening words those are... Anyway, with the advent of autosegmental phonology, a whole new world was opened up with respect to tone, vowel harmony, gemination, Arabic, and many other linguistic phenomena. With respect to tone, what autosegmental phonology does is it allows us to talk about tones as something separate from the actual phonological form of a word. Before, tones were thought of as features of vowels, and this caused all sorts of problems, 'cause, man, tones are their own thing, and they float along of their own free will, not listenin' to what no consonant or no vowel does or don't do, dig?
So here's what the upshot is. Take a word like mula, "to release". Both its vowels carry a low tone. There are two ways of saying this: (a) Each vowel has a feature "low tone"; or (b) the whole word has a low melody, and the result of this is that each vowel has a low tone associated with it. According to things like the OCP and the Twin Sisters Convention, it's better to go with hypothesis (b), but, unfortunately, Njaama can't show you why... A shame, that. Moving on...
Njaama words are a conglomeration of two things: Accents and pitch drops. Some have both, some have just an accent, and some have neither. So, for example, a word with all low vowels, like mula, has neither. As a result, a default tone is inserted, and this default tone is low, so all the vowels in the word have a low tone.
Now, let's see words with just an accent. Take mbotú, "guy", and pálá, "tower". In mbotú, the accent is on the last vowel. If any vowels were to follow it, they'd have high tones as well, since all vowels following an accent are high. This we can see in pálá, where the accent is on the first syllable.
The last type of word is a word that has an accent and a pitch drop. This is an extremely common type. So, take the word for "one", háme. This word has an accent on its first syllable, but a pitch drop on its second. All the syllables that follow the pitch drop would be low, as well.
That's how the tone system works for stems.