Language dependent (customized) text in bibliography (error with \DefineBibliographyStrings{language} and broken \iffieldequalstr{hyphenation})

Question

I'm trying to get a language dependent (customized) text in biblioraphy with pdflatex (biber).

I've found at least 3 approaches to do this by means of:

1. \DefineBibliographyStrings{language}{bibfield={formatting}}
2. \NewBibliographyString - create new bibstring and use it like in this example
3. \iffieldequalstr{hyphenation}{language}{true}{false}

However, first approach

\DefineBibliographyStrings{english}{series = {Ser\adddot\addcolon\space{#1}\isdot}}

\DefineBibliographyStrings{russian}{series = {Сер\adddot\addcolon\space{#1}\isdot}}

leads to the error:

Package keyval Error: series undefined. }

Second approach is hard to implement if you have a lot of text tuples to be customizied.

Third approach

\DeclareFieldFormat{series}{\iffieldequalstr{hyphenation}{russian}{Сер}{Ser}\adddot\addcolon\space{#1}\isdot} % 

does not work with any laguage-oriented field like hyphenation.

Please, help me with the answer, which solves problems with 1 and 3 approaches.

MWE

\documentclass{memoir}

\usepackage{filecontents}

\begin{filecontents}{\jobname.bib}
@INBOOK{Inbook,
  author       = {Peter Eston},
  title        = {The title of the work},
  booktitle    = {Book title},
  chapter      = {8},
  pages        = {201-213},
  publisher    = {The name of the publisher},
  year         = {1993},
  volume       = {4},
  series       = {5},
  address      = {The address of the publisher},
  edition      = {3},
  month        = {7},
  hyphenation     = {english}
}

@Book{avtonomova:fya,
  author = {Н. С. Автономова},
  title = {Философский язык Жака Деррида},
  year = 2011,
  publisher = {Российская политическая энциклопедия (РОССПЭН)},
  location = {М.},
  isbn = {978-5-8243-1618-6},
  series = {Российские Пропилеи},
  pagetotal = 510,
  hyphenation =russian,
}
\end{filecontents}

\usepackage[T2A,T1]{fontenc}
\usepackage[utf8]{inputenc}[2014/04/30]         %
\usepackage[english, russian]{babel}[2014/03/24]% 


\usepackage[%
backend=biber,
bibencoding=utf8,
style=gost-numeric,
babel=other, 
defernumbers=true,
sortcites=true,
doi=true,
]{biblatex}[2016/09/17]
%add Ser.: to series format

%%% First approach
%\DefineBibliographyStrings{english}{series = {Ser\adddot\addcolon\space{#1}\isdot}}
%
%\DefineBibliographyStrings{russian}{series = {Сер\adddot\addcolon\space{#1}\isdot}}


%%% Third approach
\DeclareFieldFormat{series}{\iffieldequalstr{hyphenation}{russian}{Сер}{Ser}\adddot\addcolon\space{#1}\isdot} % do not work

%% Work perfectly
%\DeclareFieldFormat{series}{\iffieldequalstr{pagetotal}{510}{Сер}{Ser}\adddot\addcolon\space{#1}\isdot} %
\addbibresource{\jobname.bib}

\begin{document}

\cite{avtonomova:fya,Inbook}

\printbibliography

\end{document}

Desired output

Answer 1

Note first that you must give non-numeric values in the .bib file with curly braces (or quotation marks). hyphenation = russian is wrong and produces the warning WARN - BibTeX subsystem: <filename>, line 29, warning: undefined macro "russian". It should be

hyphenation = {russian},

---

The \iffieldequalstr{hyphenation}{russian} does not work because hyphenation is a legacy alias. Internally the field is now called langid. Hence,

\iffieldequalstr{langid}{russian}

works.

I would, however, prefer an approach with bibliography strings. Since the string series is not yet defined you need to declare it first with \NewBibliographyString{series}. Then you can give its definition in \DefineBibliographyStrings. Note that this definition should only contain the translated string, no additional punctuation and no other macro-like formatting. Finally you can use the string with \bibsring in the field format. This is basically the second approach from Creating new commands inside the bibfile.

\documentclass{memoir}
\usepackage[T2A,T1]{fontenc}
\usepackage[utf8]{inputenc}[2014/04/30]         %
\usepackage[english, russian]{babel}[2014/03/24]%

\usepackage[%
  backend=biber,
  style=gost-numeric,
  babel=other,
  defernumbers=true,
  sortcites=true,
  doi=true,
]{biblatex}[2016/09/17]

\NewBibliographyString{series}
\DefineBibliographyStrings{english}{series = {Ser\adddot}}
\DefineBibliographyStrings{russian}{series = {Сер\adddot}}

\DeclareFieldFormat{series}{\bibstring{series}\addcolon\space{#1}\isdot}

\usepackage{filecontents}
\begin{filecontents}{\jobname.bib}
@INBOOK{Inbook,
  author       = {Peter Eston},
  title        = {The title of the work},
  booktitle    = {Book title},
  chapter      = {8},
  pages        = {201-213},
  publisher    = {The name of the publisher},
  year         = {1993},
  volume       = {4},
  series       = {5},
  address      = {The address of the publisher},
  edition      = {3},
  month        = {7},
  hyphenation  = {english}
}
@Book{avtonomova:fya,
  author      = {Н. С. Автономова},
  title       = {Философский язык Жака Деррида},
  year        = 2011,
  publisher   = {Российская политическая энциклопедия (РОССПЭН)},
  location    = {М.},
  isbn        = {978-5-8243-1618-6},
  series      = {Российские Пропилеи},
  pagetotal   = 510,
  hyphenation = {russian},
}
\end{filecontents}
\addbibresource{\jobname.bib}

\begin{document}
\cite{avtonomova:fya,Inbook}

\printbibliography
\end{document}

Note that the third approach gets out of hand quickly if you want to add a third language. The first approach simply does not work because biblatex separates localisation (bibstrings) and general formatting (field formats etc.). But the second approach is not a lot more work than the first approach. In fact you even avoid code duplication in this example.