If you need switch to Portuguese - language for ours component vehicle manager - you now need install Joomla Portuguese language pack.
After that please go to Joomla language manager and please set Portuguese - as yours default site language - and ours component vehicle manager - will change self interface to Portuguese.
If you will see some spell mistake - please correct that in language file.
For set in Joomla two languages - you need install extension like falange or install Joomla Language module.
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