vTiger is a popular CRM system for everybody who wants to have the system under control. There are versions for free and editions for money. vTiger CRM system is being used worldwide, which caused requiest to translate the system interface into different languages. vTiger has functionality for translating into your language manually, but it takes a lot of time and you should consider translating it into your local language using ready-made translation pack.
In my case I have default settins and my interface is in english, but I want to run vTiger in czech language.