I've taken some time to look through the English gradual as well as having seen plenty of the true gregorian melodies with their latin text. Can anyone help to understand what the pros and cons are of using the english chants? Some of my own thoughts:
The english chants do tend to be a bit easier melodically than the gregorian melodies, the language would be familiar to people, and if you don't have the resources to start putting together pamphlets for every mass for the congregation with the english translation of the latin propers, but want to start getting people used to hearing chant and the beauty it gives the liturgy, then it may be a good choice.
However, I think alot of the melodies in the english gradual can get fairly boring, since many follow just psalm tone chanting. Even though singers would already know English, it doesn't mean they will know how to pronounce it properly. It may be harder to get them sing english correctly than it would be to teach them to sing latin. You would have to break regional english speaking habits which is usually very difficult.

So far my thought has been that it might be better to be patient and take the time to really teach a new choir how to sing the true gregorian melodies with the latin meant for them and start planning for the making of pamphlets for the church before starting to actually sing the chants. I think learning settings of the ordinary would be first priority (at least two, one for penitential seasons and one for festal seasons) and getting the priest to start singing at least parts of the mass in english. THEN start moving them toward learning the more difficult chants.
Let me know what you all think.