And also with spiritu tuo?

Firstly, this is not an exercise in comparing rites. Sometimes that gets a bit futile. This post is on a topic of its own. Last night, I watched a Mass on EWTN. EWTN is blessed with good and holy priests who approach the Holy Sacrifice with an obvious fear and trembling. However, I am having trouble understanding something that I observed. At certain times the 'Dominus vobiscum' was said in Latin, and at others, in the vernacular. The priests at EWTN would know of the incorrect rendering of the Latin in the 'and also with you' (quoque tecum?) Surely in that case, they should all be said in Latin? If only for the benefit of the people's Latin, and thus completely conforming with the wishes of the Council? I don't know. I do know that I don't like hybrids - even in the Classical Liturgy; I am a strong advocate of the readings being said once, and said in Latin. After all, the Lord has gifted the Roman Church with Latin as her sacred language, let us enjoy it! Let us use it. AMDG.