So, here's the text for the first half of the second of Tolkien's two contributions to the Linguaphone Institute set of English language lessons from circa 1930.
In this recording, Tolkien and A. Lloyd James switch places, so that Professor James is the speaker of this first part. I'm no expert in old tech talk, but the part about "a five-valve set" sounded rather odd to my ear. Based on my grandfather's old set inherited by my cousin, I'd guess that perhaps what we call vacuum tubes the British called valves. And it is rather amusing to hear the plug for the Linguaphone itself in this final piece in the fifteen-record set.
To follow: the dialogue between Tolkien and James about the wonders of 'wireless'.
Lesson Thirty: "Wireless"
PART I. DESCRIPTION.
"Wireless," or "Radio" as it's sometimes called, is the most wonderful discovery in an age of discoveries. Seated comfortably in your home, you can hear music, lectures, and news broadcast hundreds of miles away. By means of wireless telephony, you can carry on a conversation with a friend on the other side of the world.
I listen in almost every evening. I began, like most amateurs, with a simple crystal set with ear-phones and an outdoor aerial attached to the roof, but now I have a five-valve set, with an indoor frame-aerial and loud-speaker. The results are excellent. I can cut out the local station quite easily and have no difficulty whatever in getting almost any station I like in Europe. I don't profess to know anything of the technical side of the business. One of my friends -- Hughes -- talks very learnedly about long and short wave lengths, dials, batteries, condensers, oscillators, self-induction and other coils, switches, high and low tension, but it's all Greek to me. I know just about enough to turn the knobs and tune in to the station I want.
I use my wireless set a good deal for keeping up my foreign languages: I find it a very useful addition to the Linguaphone Courses. When I want to hear German, I tune in to somewhere in Germany. France gives me French, Spain Spanish and Italy Italian. And what a blessing wireless has been in times of disaster at sea. Thousands must owe their lives to this discovery of the twentieth century.