documentclass{article}
usepackage{xcolor}
usepackage{listings}
begin{document}
lstinline[language=algol,keywordstyle=color{blue}]{int a}
end{document}

documentclass{article}
usepackage{xcolor}
usepackage{listings}
begin{document}
lstinline[language=[60]algol,keywordstyle=color{blue}]{integer a}
end{document}

Runaway argument?
{integer a} end {document}