Why Use Latin When the Liturgy is in English?

I have this on order from amazon.com:

Where late the sweet birds sang: Latin Music from Tudor England by Magnificat directed by Philip Cave frrom Linn Records

Per the "liner" notes, Magnificat is exploring a little mystery--why was church music written to Latin texts when the official liturgical language was English? Of course, Latin was still an important diplomatic and scholarly language in the sixteenth century, but music for the Church of England's Book of Common Prayer should have been set for English texts.

The early Elizabethan years present a fascinating period of stylistic transition in vocal music to sacred Latin texts, as well as posing some intriguing questions about context. For whom was this Latin music written, given that one of the first pieces of legislation in the new Queen's reign was the Act of Uniformity, which specified that church services should be held in English rather than in Latin, in all but a few places? And what was the practical impact of the new religious laws on composers such as Thomas Tallis, Robert Parsons, Robert White and William Byrd?

While Byrd's lifelong commitment to the Catholic faith is well documented, little is known for certain about the religious convictions of the other composers. The debate continues on whether they favoured Latin texts because they were writing for institutions where some of these texts were still permitted, because they retained loyalty to the Catholic faith, alternatively that they had in mind domestic or devotional music-making, or simply because they had an enduring affection for the old ways. Whatever its intended destination, the music's structure shows a move away from the ritual plainchant cantus firmus-based hymns and responds of Mary's chapel towards freely composed imitative polyphony in which text and music are much more closely connected. It seems to have taken noticeably longer for composers of English-texted sacred music to move on from the artistic constraints of Edwardian Protestantism to produce works of comparable musical interest (though there are, of course, a few notable exceptions to this generalisation, such as Tallis's miniature masterpiece "If ye love me"). 

We are lucky to have this music and to have Magnificat record it:

Much of the music presented here is known to us not through sources compiled for use in church - hardly any have survived - but because it was included in one or other of the largely retrospective manuscript collections now in the library of Christ Church, Oxford, assembled by Robert Dow (Mss.984-88, c.1581 - 88) and John Baldwin (Mss.979-83, c.1575 - 81). Although dating individual works with certainty is rarely possible, most of the music chosen for this recording is thought to come from the 1560s and 70s. . . .

Considering and compiling this recording is something that has occupied my thoughts over several years. Both in content and performing style it represents the fruits of a personal journey that started at a time when most of this music was not at all widely known. None of us dared to dream then that it could ever be shared with the thousands of people who have now come to value it. Time moves on, and witnessing that positive progress gives cause for some satisfaction.

Overall, the mini-trend of performing groups like the Tallis Scholars, Stille Antico, Magnificat, The Tudor Consort, The Byrd Ensemble, and others, reflecting on the religious conflict during the sixteenth and seventeenth centuries is fascinating to me.

You might notice the Shakespearean reference in the CD title:

That time of year thou mayst in me behold
When yellow leaves, or none, or few, do hang
Upon those boughs which shake against the cold,
Bare ruined choirs, where late the sweet birds sang.
In me thou see'st the twilight of such day
As after sunset fadeth in the west;
Which by and by black night doth take away,
Death's second self, that seals up all in rest.
In me thou see'st the glowing of such fire,
That on the ashes of his youth doth lie,
As the death-bed, whereon it must expire,
Consumed with that which it was nourish'd by.
This thou perceiv'st, which makes thy love more strong,
To love that well, which thou must leave ere long.

Eamon Duffy parsed that line, "Bare ruined choirs, where late the sweet birds sang" to identify William Shakespeare with a sort of nostaglia for the monasteries and lost Catholic culture, in his book Saints, Sacrilege, and Sedition last year. This reviewer Professor David J. Davis, thinks it too much a throwaway:

Finally, the chapter, almost whimsically, speculates about the bard himself, seeking to include him in this expanding cabal of conservative voices. Despite Duffy's disclaimer that he is not arguing ‘that Shakespeare was a Catholic’, he does interpret Sonnet 73 as one that ‘decisively aligns Shakespeare against the Reformation’ (pp. 253, 250). Assuming this is true, that a single sonnet captures Shakespeare’s views of the Reformation, which is a grand and hasty assumption, Duffy does not propose what this means for the Stratford dramatist’s religious creed. Duffy’s argument is little more than a playful suggestion, based upon a single line in a single poem, but it is, in the end, more a scholarly flight-of-fancy than the kind of historical nuance we have come to expect from Duffy’s analysis. Moreover, it is a somewhat limp method of wrapping up the entire book, leaving readers with something much more akin to a sigh than a bang.