\version "2.19.80"

\new ChoirStaff <<
  \new Staff \with {
    instrumentName = \markup \column { "Soprani" "o Tenori" }
  } {
    s1
  }
  \new Staff \with {
    instrumentName = \markup \column { "Contralti" "o Bassi" }
  } {
    s1
  }
>>