The non-english speaker under the church

[Ashtoreth]

I think Ashtoreth may be right, it's probably esperanto. I know it's not spanish or any sort of indigenous language.

Personally, I think he may be a priest

Actually I am thinking more of glossolalia, as I explained when I edited my post.
This type of "speaking" is used in many faiths, including Shamanism. Aztecs and Mayans practised shamanistic rituals so there might be some sort of connection.