Reply To: How to configure BP front-end user menu
Site language is the reference. Go to Settings > General and choose your site language.
If you use es_AR, you should use buddypress-es_AR.mo
If you use es_ES, you should use buddypress-es_ES.mo
and so on…
At each update, language files are also updated. This means that if you use bp-es_VE and the site is declared as using es_AR, your bp file will be updated to es_AR and BP will use this one instead bp-es_VE.
It would be better you use same language for site and plugins. What you can do, is to rename es_VE to buddypress-es_AR.po/mo. You need also to modify accordingly the header information in the po file. To do that you need to use poEdit to compile it to mo and get the correct header in it.
Note also that BP translation should be installed in wp-content/languages/plugins/buddypress-xx_XX.mo
