Downstep
Downstep is a phenomenon in tone languages in which if two syllables have the same tone (for example,
both with a high tone or both with a low tone), the second syllable is lower in pitch than the first.
Two main kinds of downstep can be distinguished. The first, more usually called automatic downstep,
downdrift[1] or catathesis,[2] occurs when high and low tones come in the sequence H L (L) H; the
second high tone tends to be lower than the first because of the intervening low toned syllable. That
phenomenon is common in African languages, such as Chichewa.[3] It has also been argued that the
same phenomenon is heard in English sentences, if these sentences are pronounced with a falling
intonation, for example I really believe Ebenezer was a dealer in magnesium, or I bought blueberries,
bayberries, raspberries, mulberries, and brambleberries.[4][5]
Downstep proper, or non-automatic downstep,[6] is another phenomenon found in many African
languages such as Igbo. [7] for an overview of downstep in African languages.) If two high tones are in
succeeding syllables (thus in the sequence H H), and the second is lower than the first, there is said to be
a downstep.[8]
The symbol for the second kind of downstep in the International Phonetic Alphabet is a superscript
down arrow, ⟨ ꜜ⟩ . It is common to see instead a superscript exclamation mark ⟨ ꜝ ⟩ because of
typographic constraints, though technically that would mean an incompletely or lightly articulated
alveolar click release.
It has been shown that in most, if not all, cases of downstep proper, the lowering of the second high
tone occurs when an intervening low-toned syllable has dropped out. What was H (L) H has become
HꜜH.[9] The missing low-toned syllable creates what is known as a ‘floating tone’. An example occurs in
Bambara, a language spoken in Mali. In Bambara, the definite article is a floating low tone. With a noun
in isolation, it docks to the preceding vowel and turns a high tone into a falling tone:
/bá/
river
/bâ/
the river
However, when it occurs between two high tones, it downsteps the following tone:
/bá tɛ́/ it’s not a river
/bá ꜜ tɛ́/
it’s not the river