\version "2.19.25"

alto = \relative {
  <<
    { d'2\melisma e4\melismaEnd cis }
    \new Voice { \voiceTwo s1 }
  >>
}

altText = \lyricmode {
  side, sit
}

\score {
  <<
    \new Staff \alto
    \addlyrics \altText
  >>
}

% exactly the same, but without using a variable for the music
\score {
  <<
    \new Staff \relative {
      <<
        { d'2(\melisma e4)\melismaEnd cis }
        \new Voice { \voiceTwo s1 }
      >>
    }
    \addlyrics \altText
  >>
}