German umlaut in the language-field in the bibliography

Question

If I place a german umlaut like e.g. "ü" in the language-field of a biber entry, and if I then run biber & pdflatex the way I usually do, I get the following error:

Missing \endcsname inserted

There's no difference whether I input a plain "ü" or I use \"{u} or {\"u}. Also, changing the entry-type doesn't change things.

The interesting thing about this behaviour: placing an "ü" into one of the more common fields (like author for example) doesn't produce any error at all and works fine with many entrys for me.

I'd like to have the word "Frühneuhochdeutsch" in the language-field; any suggestions?

MWE:

The bibliography:

@Misc{Habsburg95DieHandhabungdesa,
  Title                    = {Handhabung},
  Author                   = {Maximilian I. von Habsburg},
  Language                 = {Frühneuhochdeutsch},
  Month                    = {aug},
  Year                     = {1495},

  Timestamp                = {2014-01-19}
}

The document:

\documentclass[a4paper,10pt,twoside]{article}
\usepackage[utf8]{inputenc}
\usepackage[ngerman]{babel}
\usepackage[babel,german=guillemets]{csquotes}
\usepackage[
backend=biber,
style=alphabetic,
natbib=true,
]{biblatex}
\addbibresource{bibliography.bib}
\usepackage{lipsum}

\begin{document}

\lipsum[1] \cite{Habsburg95DieHandhabungdesa}

\newpage

\printbibliography

\end{document}

Answer 1

use language=auto or one of the predefined languages in table 4 of the biblatex documentation.