I recall as a thirteen year old hearing Butterfly in English on the radio.
I was able to catch most of the words and it was magic completely turning
me on to opera.  I could not afford full opera sets but working for a local
farmer gave me enough pocket money to save up for 10" LPs by Joan Hammond,
Bjorling etc.  I then used to buy complete libretti from EMI so I could
follow the arias.  They were cheap then and I always regretted the way
record companies stopped making libretti available separately.  I also seem
to recall when I bought the mono Britten/Pears Serenade for Tenor, Horn and
Strings that the words were only available as a separate purchase.  Can
anyone back me up in that?

When I moved into cassette I used to insist record companies sent me the
booklet or the sleeve of the LP if the texts were available there but not
to cassette purchasers (quite common then).  There was never any trouble
getting them.  Similarly, DGG actually shipped over for me the German
gatefold sleeve to the Maazel L'enfant et les sortileges as the UK sleeve
was different.

Len