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 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 causes English sentences, such as I really believe Ebenezer was a dealer in magnesium or I bought blueberries, bayberries, raspberries, mulberries, and brambleberries (if the sentences are pronounced with a falling intonation), to fall gradually in pitch, with each accented syllable (here underlined) slightly lower than the last.^[4]

Downstep proper, or non-automatic downstep^[5], is another phenomenon found especially in West African languages such as Igbo. If two high tones are in succeeding syllables (thus in the sequence H H), the second is lower than the first.^[6] In such languages, when two high tones come one after the other, they are at the same height or, if there is a downstep, the second one is lower. The second high tone is also lower than the preceding one if there is an intervening low tone in the sequence H L H as described above. The high tones in a simple sentence tend to descend from the beginning to the end of the sentence in a series of steps, a phenomenon that Is known as tone terracing.

The symbol for the second kind of downstep in the International Phonetic Alphabet is a superscript down arrow, (^↓). It is common to see instead a superscript exclamation mark (^!) because of typographic constraints.

It has been shown that in most, if not all, cases of downstep proper, the lowering of the second high tone is from an intervening low-toned syllable that has dropped out. What was H L H has become H H.^[7] The missing low-toned syllable creates what is known as a 'floating tone'. An example occurs in Bambara, a language spoken in Mali. Its 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:

However, when it occurs between two high tones, it downsteps the following tone:

The Japanese pitch accent may be compared to that. About 80% of Japanese words have an evenly rising pitch, something like in French, which carries over onto a following unstressed grammatical particle. However, about 20% of words have a drop in pitch between syllables, or before a grammatical particle:

In isolation, the first word has a high-low pitch, and the second and third are homonyms, with a low-high pitch. (The first syllable is low only when the word is said in isolation.) However, all three are distinct when they followed by the nominative particle ga:

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