% Now, switch on what is appropriate for czech:

% czech quotation marks
% \bq - begin quotation, \eq - end quotation
\def\bq{\mbox{\kern.1ex\protect\raisebox{-1.3ex}[0pt][0pt]{''}\kern-.1ex}}
\def\eq{\mbox{\kern-.1ex``\kern.1ex}}
%\setlanguage{\czech}

{%                                      % Begin a group for which " is active
\catcode`\"=\active                     % Make " an active character
\catcode`\@=11                          % Make @ an active character
%
%  \csdoublequoteson
%
%       This macro makes " an active character, resets the control sequence
%       \dblqu@te to L (left), and defines \dq as a replacement for ".
%
\gdef\csdoublequoteson{%                % \csdoublequoteson enables "
    \gdef"{\czechquotes}%               % Define " as \czechquotes
    \global\catcode`\"=\active%         % Make " an active character
    \global\chardef\dq=`\"%             % Double-quote char. via \dq
    \global\let\dblqu@te=L%             % Always start with a left double-quote
    }                                   % End of macro
%
%  \bq, \eq
%
%      These macros define default characters for czech left and right
%      double quotes. Czech opening quote is created from two commas with
%      kerning depending on fontdimen four parameter of current font.
%      Better solution should be specially designed character with
%      proper kernings; if you have such characters in fonts
%      (e.g. in DC-fonts), use it instead. (e.g. define
%      macros \bq and \eq e.g. \def\bq{\char"130 }
%      in your document/style file-- not in csquote.sty!)
%      Similar solution is used for czech right quote.
%
%      \cs existence test, stolen from TeXbook exercise 7.7
\def\ifundefined#1{\expandafter\ifx\csname#1\endcsname\relax }%
%
%      another macro to be more efficient in time and space
\global\chardef\f@@r=4
%
\ifundefined{bq}%
\gdef\bq{\kern-.25\fontdimen\f@@r\font,\kern-.8\fontdimen\f@@r\font,%
                \kern-.35\fontdimen\f@@r\font}%
\fi
\ifundefined{eq}%
\gdef\eq{\kern-.35\fontdimen\f@@r\font`\kern-.8\fontdimen\f@@r\font`%
                \kern-.25\fontdimen\f@@r\font}
\fi
%
% Macro \uv for other usage of \bq and \eq.
%
\ifundefined{uv}%
        \gdef\uv#1{\bq #1\eq}
\fi
%
% \testquotes macro gives warning if citation span this place
%
\gdef\testquotes{\if R\dblqu@te
        \message{Warning: You forgot right double quote!}%
        \let\dblqu@te=L\fi}
%
%  Define the macro that will be executed whenever " is encountered.
%
\gdef\czechquotes{\protect\czechqu@tes}
\gdef\czechqu@tes{%
        %  If the double-quote is the first character in a new paragraph,
        %  make sure it becomes a left double-quote.  This case can be
        %  detected by checking to see if TeX is currently in vertical mode.
        %  If so, the double-quote is at the beginning of the paragraph
        %  (since " hasn't actually generated any horizontal mode tokens
        %  yet, TeX is still in vertical mode).  If the mode is vertical,
        %  set \dblqu@te equal to L.
        %
        \ifinner\else\ifvmode\testquotes\fi\fi%
        %
        %  Now insert the appropriate left or right double-quote.
        %
        %  If \dblqu@te is L, insert an opening quote and set \dblqu@te to R.
        %
        \if L\dblqu@te\bq\global\let\dblqu@te=R%
        %
        %  Otherwise, save the current \spacefactor, insert '', set \dblqu@te
        %  to L, and reset the original \spacefactor.
        %
        \else%
           \let\xxx=\spacefactor%               % Save the \spacefactor
           \eq%                                 % Insert ending quote
           \global\let\dblqu@te=L%              % and reset \dblqu@te
           \spacefactor\xxx%                    % Reset the \spacefactor
        \fi%                                    % End of \if L\dblqu@te...
        }                                       % End of " macro
}                                               % End of group

\gdef\csdoublequotesoff{%
        \catcode`\"=12%                         % Set " back to other
        }
%
% Czech quotes are default
%
\csdoublequoteson