Lyric aligment problem

[Illtud Daniel]

I'm getting lyrics left-aligned to noteheads with autobeaming off.
This is what I've got:

\version "2.10.13"

\score  {

<<
\new Voice = "alaw"
\relative c''
 {
        \time 2/4
        \key g \minor
        \clef treble

        \autoBeamOff

        bes8[ d d c] |
        bes[ d ees d16 d] |

        \bar "||"
}

\new Lyrics \lyricmode {

        Ar8 ddydd Sul aeth
        Dic yn ben -- noeth16 mewn

} >>
}


Is this a bug, or my problem? Can I fix it?

Also, with languages with a different vowel set (this is
Welsh!) is there a way I can tell lilypond about these
so that the 'first vowel notehead alignment' works properly
with 'aeouiwy' - the Welsh vowel set?

Thanks.

--
Illtud Daniel                                 address@hidden
Uwch Ddadansoddwr Systemau                       Senior Systems Analyst
Llyfrgell Genedlaethol Cymru                  National Library of Wales
Yn siarad drosof fy hun, nid LlGC   -  Speaking personally, not for NLW