Good Morning,
I wondered why my spanish members all opt out of Private Messaging! 
There is a little trick in the Private Message settings in Member Profile.
In english it says: Opt out of Private Messaging
In spanish it says: Optar por Mensajería Privada, meaning the contrary, meaning opt in for Private Messaging.
So spanish speaking members opting for Private Messaging are consequently opting out activating the red button!!
Where exactly can I change the frase?
Thank you.
Nasty… it will need to be updated/corrected on the translation site (http://glotpress.simple-press.com), validated and then a new, refreshed .mo file generated. This will be the Private Messaging plugin po/mo files.
Well, Google has its own languages. l.o.l.
o.k. I tried to suggest the correct translation in http://glotpress.simple-press.com/projects/simple-press-plugins/private-messaging/sp-pm/es/default?page=8
but I am not sure if I have done it right. The legal translation would be: Optar por excluirse de la Mensajería Privada. It will have to get validated as you said.
Hope this helps….
I found two translations on the translation site. The correct one is highlighted in yellow. 
well, now we just need a language translation validator to approve them… that’s not us since we don speak the language…
If you wanted to volunteer to be a language translator, we can add you in and you can approve… just need your username for our glotpress site…
Certainly I feel honored, it’s quite a responsibility and will take some time if it means that this is a translation job.
But yes of course, if you trust me, I’ll do my very best.
Username is the same than here. polkita.
I have added you as a translator for Spanish on core, plugins and themes… thanks!
um, its automatic… just download the new .mo file from glotpress… at the bottom is a export link… select .mo and away you go… thanks!
Now it works. My spanish members are getting what they want in Private Messaging. 
Thank you very much.