From Wikimedia Incubator
Babel user information
en-N This user has a native understanding of English.
pt-4 Este utilizador tem um nível quase nativo de português.
es-3 Esta persona tiene un conocimiento avanzado del español.
Users by language

I don't know what the difference levels of language understand correspond to, so I put "3" for Spanish and Portuguese. I am fluent in Portuguese (as a learned language), and am advanced in Spanish.