\documentclass{article}

\usepackage[T1]{fontenc}
\usepackage[french,spanish,english]{babel}
\usepackage{datetime} % Date will be language-dependent
%\usepackage[iso]{datetime} % Date will be displayed the same for all languages

\begin{document}
English: \today

\selectlanguage{french}
French: \today

\selectlanguage{spanish}
Spanish: \today

\begin{otherlanguage}{french}
French: \today
\end{otherlanguage}

\today
\end{document}
