\documentclass[a4paper,frontgrid]{flacards}
\usepackage{color}

% redefining center head on frontside
\renewcommand{\fchead}{%
 \vskip-3pt\fboxsep=0pt%
 \colorbox{red}{%
  \small\sffamily\bfseries\textcolor{white}{%
   \parbox{\cardwidth}{\vskip3pt\centering Deutsch\vskip4pt}%
  }%
 }%
}

% redefining center head on backside
\renewcommand{\bchead}{%
 \vskip-3pt\fboxsep=0pt%
 \colorbox{blue}{%
  \small\sffamily\bfseries\textcolor{white}{%
   \parbox{\cardwidth}{\vskip3pt\centering Espa\~nol\vskip4pt}
  }%
 }%
}

% redefining default text style for front side
\renewcommand{\cardtextstylef}{\bfseries}


% You can define head and foot elements using \flhead, \fchead 
% and \frhead for right, center and right head on frontside,
% \flfoot, \fcfoot, \flfoot for footline on frontside. 
% Analogical use \blhead, \bchead, \brhead, \blfoot, \bcfoot 
% and \frfoot for backside.

\begin{document}
% 2x4 cards per page
\pagesetup{2}{4}

% change layout for left foot on front
\renewcommand{\flfoot}{\footnotesize Grammatik} 

\card{Conjugation (pret\'erito imperfecto, regular)}
{\begin{tabular}{l|ll}
                  & cocin{\bfseries ar}       & viv{\bfseries ir}\\
\noalign{\hrule height 1pt}%------------------------------------------
yo                & cocin{\bfseries aba}      & viv{\bfseries \'ia}\\
t\'u              & cocin{\bfseries abas}     & viv{\bfseries \'ias}\\
usted, ella, \'el & cocin{\bfseries aba}      & viv{\bfseries \'ia}\\
nosotros/-as      & cocin{\bfseries \'abamos} & viv{\bfseries \'iamos}\\
vosotros/-as      & cocin{\bfseries abais}    & viv{\bfseries \'iais}\\
ustedes, ellos/-as& cocin{\bfseries aban}     & viv{\bfseries \'ian}\\
\end{tabular}
}

\card{Conjugation (pret\'erito imperfecto, irregular)}
{\begin{tabular}{l|lll}
                  & ser      & ir       & ver\\
\noalign{\hrule height 1pt}%------------------------
yo                & era      & iba      & ve\'ia\\
t\'u              & eras     & ibas     & ve\'ias\\
usted, ella, \'el & era      & iba      & ve\'ia\\
nosotros/-as      & \'eramos & \'ibamos & ve\'iamos\\
vosotros/-as      & erais    & ibais    & ve\'iais\\
ustedes, ellos/-as& eran     & iban     & ve\'ian\\
\end{tabular}
}

\renewcommand{\flfoot}{\footnotesize Vokabeln} 
\card{gehen}{ir}
\card{sein}{ser/estar}
\card{Land}{pais, {\em m}}
\end{document}