https://texwelt.de/wissen/fragen/24268/biblatexbiber-deutscher-autorenname-eines-bibliographie-eintrags-englischer-rest

sort.tex

\documentclass[ngerman]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{babel}
\usepackage{csquotes}

\usepackage[style=authoryear, backend=biber]{biblatex}


\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@book{krager,
  author  = {Frederike Krager},
  title   = {German a},
  date    = {1970},
  langid  = {ngerman},
}
@book{kroumlger:de,
  author  = {Frederike Kröger},
  title   = {German ö},
  date    = {1980},
  langid  = {ngerman},
}
@book{kroeger,
  author  = {Frederike Kroeger},
  title   = {German oe},
  date    = {1981},
  langid  = {english},
}
@book{kroegler:nl,
  author  = {Frederike Kroegler},
  title   = {Dutch oe},
  date    = {1982},
  langid  = {dutch},
}
@book{kroumlgler:se,
  author  = {Frederike Krögler},
  title   = {Swedish ö},
  date    = {1983},
  langid  = {swedish},
}
@book{krper:de,
  author  = {Frederike Krper},
  title   = {German p},
  date    = {1983},
  langid  = {ngerman},
}
@book{kroger,
  author  = {Frederike Kroger},
  title   = {German o},
  date    = {1983},
  langid  = {english},
}
@book{krogfuhr,
  author  = {Frederike Krogfuhr},
  title   = {German o},
  date    = {1983},
  langid  = {english},
}
\end{filecontents}

\addbibresource{\jobname.bib}


\begin{document}
\nocite{*}
\printbibliography
\end{document}