From a reader…
My Latin is not great will an ordinary form mass I celebrate in Latin be valid?
Sure, Father, it would be valid.
Language is a tricky thing. There are almost always gaps in our comprehension of texts, even in our own, native language. Moreover, with Holy Mass we are dealing with mysteries, which by definition are hard.
One of ways that narrow-minded bishops hostile to tradition attempted to block the implementation of Summorum Pontificum – issued 10 years ago tomorrow! – was to try to impose a Latin language test on priests or they wouldn’t be permitted to use the 1962 Missale Romanum. Benedict XVI’s Motu Proprio said that priests have to be idoneus which means “suitable” for celebration of Mass. Tradition-hostile bishops took that to mean “expert in Latin” or such-like. Of course those bishops, who probably couldn’t have passed the test themselves, didn’t impose tests on priests who said Mass in Spanish.
As an aside, let’s start testing to see if priests really understand what they are saying in the Novus Ordo. Let’s see if they really know the few clear rubrics there are, according to the 2000 GIRM. Let’s quiz priests about the content of the prayers and the underlying concepts. Let’s see if every priest from overseas really understands the English or can if he pronounce it clearly before he is allowed to say Mass in public. Let’s ask these bishops if they insist with the rectors of seminaries that their seminarians are properly trained in Latin according to can. 249.
Additionally, as it was clarified, idoneus or “suitable” doesn’t require expertise. Rather, it establishes a minimum rather than a maximum requirement. The late Card. Egan, a canonist who was not particularly friendly to tradition, clarified that idoneus meant that he had faculties, wasn’t impeded for some reason, and was able to pronounce the words properly. As far as the Latin language is concerned, idoneus doesn’t mean that you have to be able to compose odes in the style of Horace.
In short, Father, yes, you can celebrate the Novus Ordo, Ordinary Form Mass in Latin and celebrate validly, even if your Latin isn’t very good.
Your patron saint in working on the Latin will be St. John Vianney, whose Latin was so bad that he almost wasn’t ordained.
Keep working on it! There are good resources available. Do not give up. This is the language of your Rite.
We are our rites.