Title. Is praying in latin worth anything/pleasing to God even if we don't understand the words we are saying?

A good start is the Hail Mary in Latin.

My dad dropped out of school after 4th grade, but he pretty much knew what every word in the Latin Mass means, even if he didn't understand the finer points of the inflection and grammar ... just from reading a Missal side by side.  So you'll eventually figure out the basic meaning of the words.

THIS ^^^

I wouldn't say I know Latin very well but I definitely have learned a lot just from looking at the English next to the Latin in the missal for Mass.

And as long as we offer up the Latin words and intend to do what the Church does and means by them I think that it is worth it.

Did every monk understand every Latin word while singing the Divine Office?  I doubt it...  But was it worth it?  Absolutely!

One does not have to understand the Holy Trinity to submit and agree that it is truth.

When St. Edmund Campion was on the scaffold…  Campion started to pray in Latin, but an Anglican clergyman rudely interrupted him and tried to direct his prayers according to the Protestant form.  “Sir, you and I are not one in religion, wherefore I pray you content yourself.  I bar none of prayer; but I only desire them that are of the household of faith to pray with me, and in mine agony to say one creed.”  When someone cried out that a good Englishman would pray in English instead of Latin, he retorted with his old wit, “I will pray God in a language which we both well understand.” 

[And in any case, God understands Latin even if we don't.]

Of course, your native language is what you use for meditative/mental or spontaneous prayer. Yet with vocal prayer, the forms that the Church has given us through Tradition, see below from St. Francis de Sales, Introduction to the Devout Life, Part Second, Chapter One (fyi: page 62 in the TAN 2010 edition).

I recommend you to say the Lord's Prayer, Hail Mary, and Creed in Latin. But you must at the same time thoroughly understand the words in your own language: so that whilst you join in the universal language of the Church, you may appreciate the blessed meaning of those holy prayers, which you must say, fixing your thoughts steadily, and arousing your affections, not hurrying in order to say many prayers, but endeavoring that what you say may come from your heart. For one Lord's Prayer said with devotion is worth more than many recited hastily.

There you have it from a Doctor of the Church: quality (i.e., in Latin), not quantity.

Also, the thing about Latin is all those declensions and case endings, which determine the meanings of each sentence (as to who/what is doing what by/for/from/to/with/etc.), thus precision really does matter with those final syllables. Better to take your time little by little with the Latin, glancing over at the vernacular translation as needed.

Another hint: Look online for subtitled video or audio files of well-known Latin hymns. Singing, even quietly to yourself, really does help with comprehension and recall since the words become linked in the mind with the tonality of the hymn.