Bug#647225: texlive-lang-cyrillic: missing font declaration for T2A/aer
Most likely the LaTeX code produced by Songwrite contains something
Replacing that by
should solve your problem and lead to better results wrt fonts.
Great! I found where Songwrite writes this command in its code and this
solves the issue without the (uggly) patch I did before :). I'll report
this to the upstream author and propose you close the bug.