“A community is calling its very being into question when it suddenly declares that what until now was its holiest and highest possession is strictly forbidden, and when it makes the longing for it seem downright indecent.” -Cdl. Ratzinger
In the mass, the priest speaks to God in the language of the church. The priest, both in homily and the confessional, speaks the language of the congregation. So, the advice to learn the language of the congregation is appropriate... after one learns the language of the church.