Tolkien shouted his responses loudly in Latin shortly after church services were translated to English in the 1960s, and was upset about having less Latin in liturgies, but this has more to do with his love of language than it was about him protesting anything.
This new form of the mass that many fans think he protested did not appear until 1969, a few years before his death and also after the events and quotes from his letters took place. At that time period, the identical Latin Mass was being translated to English which he would refer to in all his quotes from his letters concerning this matter – and this change took almost the entire decade to develop.
This also included sentiments from his grandson and granddaughter, Simon (who was embarrassed) and Joanna (who was unbothered), thus having very different responses with similar conclusion – that Tolkien just had to do what he thought was right.
As a result of his background, Tolkien was able to shout the responses in Latin due to having grown up with this same form, and he would do what he had always done for almost his whole life.
Tolkien would spend his final days at Merton College where he would attend the Church of St. Anthony of Padua in Headington, a Novus Ordo parish. It was unknown his exact beliefs on the mass, but he accepted them and would continue to experience a profound spiritual joy.
Love of the Latin Language and the desire to preserve it
Tolkien had a great passion for languages, including Latin, thus he didn’t like the English translations used in the liturgies. Thus, there are many different phrases in the NO as there were in the TLM, thus he believed the languages could not be switched – by giving the NO in Latin or the TLM in English.
“It is important to note that what Tolkien experienced in 1964 was not the ‘Novus Ordo’, the significantly revised liturgy that most Catholics today encounter when they hear a Mass in English…it was an essentially line-of-line translation of the Mass that he had known all his life…The Missal of 1966, for the use of the priest, makes [the translation] visible: it is in two columns, with the original Latin on the left and the new English translation on the right.” (Dr. Holly Ordway, “Tolkien’s Faith”)
Tolkien was taught Latin from his mother and along with that, he also studied them since 1911 in two Birmingham schools.
In college, Tolkien also studied other languages such as Greek, Old English, Gothic and other Germanic languages, Finnish, and Welsh. He would also continue studying Latin throughout his life, and since masses were held in Latin, Tolkien would become accustomed to praying in Latin.
His invented languages such as Quenya and Sindarin were heavily inspired by his experiences with learning languages. For example, Quenya was heavily influenced by Latin, to the point he called the language of the High Elves, “Elven-Latin.”
His son John recalled in 1992 that Tolkien “very strongly couldn’t see any point in abandoning Latin, because he spoke Latin.” (J.R.R. Tolkien, “A Film Portrait”) Tolkien simply wanted Latin to continue to be a living language as a whole.
The bottom line
Thus, his objections were purely (1) the loss of Latin as a language, and (2) the awkward English translations that replaced it – mainly because they were in bad or clumsy English. Thus, he would attempt to ignore this change entirely and continue to pray in Latin.
Even long before this change, Tolkien would form a habit of praying privately in Latin.
Fr Gerald Hanlon, who attended to Tolkien during his sick days, encountered Tolkien in 1968 in response to his speaking Latin. Tolkien said that he just “[liked] to pray to God in Latin,” as a personal preference. (Daniel Helen and Morgan Thomsen, “A recollection of Tolkien: Canon Gerald Hanlon.)
