The English translation of the Latin sentence 'Liber tuus et lectus est et legitur a me cum diligentia' is the following: Your book both has been read, and is being read, by me with care. The word-by-word translation is as follows: 'liber' means 'book'; 'tuus' means 'your'; 'et...et' means 'both...and'; 'lectus' means 'read'; 'est' means '[it] has been'; 'cum' means 'with'; and 'diligentia' means 'care'. The translation of the second sentence 'Vis autem verborum intellegi non potest' is the following: But the force of the words can't be understood. The word-by-word translation is as follows: 'vis' means 'force, power, strength', even 'violence'; 'autem'* means 'but, however'; 'verborum' means 'of the words'; 'intellegi' means 'be understood'; 'non' means 'not'; and 'potest' means '[it] can'. *The order is correct here. For the conjunction 'autem' is never to begin a sentence.
The phrase "it was Greek to you" originates from William Shakespeare's play "Julius Caesar." In Act 1, Scene 2, Casca says to Cassius, "For mine own part, it was Greek to me." This phrase is used to convey that something is difficult or incomprehensible to someone.
Denuo hanc nonam litteram lege, quaeso. Amen dico vobis, quod haec una de Graecorum litterarum est. Nomen huius graece est upsilon. Propterea eloquium tuum non latine est. Graecum a romanis non legitur. Which is to say that the letter 'y' is not a native part of the Latin alphabet so this message is meaningless in Latin. However, "ponderis" could probably be understood as important or dependable, unchanging, etc. "Domine" is vocative and is addressing the lord. To recap: your message is something like "Lord, of an important or heavy or unchanging thing, " with "you" added into the mix.