If you set up each language's form in a different program you use the {{lead.Acquisition Program}} token which will tell you which form they filled out.
We handle this issue by creating a form for each language (Contact Us-Spanish, Contact Us-English, Contact Us-French), creating a landing page for each individual country and creating a seperate alert email for each country that says in text which form/page/country the lead is from and providing the rest of the info in tokens like name, company title, etc..
Alert Smart Campaign Example:
If filled out form Spanish Contact Us and web page was Contact Us Mexico send Alert Mexico Contact Us to Sales.