Do I need a translation of my marriage certificate in Spanish for a dependant spouse visa in Thailand?

In order to get a "trailing spouse" visa/extension (where the foreign spouse of someone who legally works stays here gets a matching extension) you will most likely have to get the marriage certificate "certified" (stamped) by the peruvian embassy here, then get it translated into thai and certified as an accurate translation by the ministry of foreign affairs office here.

You also need documentation from your employer that it's okay for your spouse to "piggy back" on your visa/extension.

Your employer and/or the immigration office in your area are who you need to be talking to so you can see exactly what you need .