Traducción de ingles a español en sistema Asp.Net (falta 20% máximo)

Step 1: Create new language file

Decide which language you want to add and copy the ASP.NET Culture code from https://msdn.microsoft.com/en-us/library/ee825488(v=cs.20).aspx. For example, if you want to add Portuguese language, your culture code is: pt-PT
Go to App_GlobalResurces and copy L1.resx to L1.CULTURECODE.resx; for Portuguese it would be L1.pt-PT.resx
Open the L1.CULTURECODE.resx file with resx (XML viewer), the best would be Visual Studio Express (it's free and very useful with Titan customization) and create the translations:
Save the file
Step 2: Translate the updates

Complete Step 1 for all language files for all updates, e.g. U2600.resx, U3000.resx, U3500.resx, U4000.resx etc.

We are adding new language file with each update to keep the whole system stable. So we don't modify/edit/enlarge the files you already translated. We are adding a new file with new content.

Translation is extremely easy (it looks like translating an Excel table):