"descant" in the noun sense
1. descant, discant
a decorative musical accompaniment (often improvised) added above a basic melody
"descant" in the verb sense
sing in descant
2. yodel, warble, descant
sing by changing register sing by yodeling
"The Austrians were yodeling in the mountains"
talk at great length about something of one's interest
Source: WordNet® (An amazing lexical database of English)
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