What language do you pray in?

For centuries Christians in the western Catholic Church prayed in Latin in formal worship.
In the chapel of the ecumenical centre and at many international church gatherings a tradition has grown up of praying the Lord's Prayer all together but each in our own language. At least once during the service everyone gets to pray in their mother tongue, or in the language they feel most comfortable praying.
I've been reading alot this week about the link between good sustainable development work and nurturing mother languages. For spirituality to come from the heart, the language we pray in has to have deep meaning and imply connectedness. Not sure whether for more sustainable spirituality we should also nurture mother languages or whether perhaps the mother language of prayer itself is what needs to be nurtured.