The acoustic theory of speech production as worked out by Gunnar Fant depends on a correspondence between the vocal tract and elementary electrical circuits. But the quote below perplexes me. In what way could electrical circuit theory be informative?
This was a truly pioneering era in speech research as an outgrowth from linguistics, electrical circuit theory, psychoacoustics and information theory. (source)
Wikipedia doesn't really shed much light on the topic, even if it mentions it there:
On a theoretical level, speech acoustics can be modeled in a way analogous to electrical circuits. Lord Rayleigh was among the first to recognize that the new electric theory could be used in acoustics, but it was not until 1941 that the circuit model was effectively used, in a book by Chiba and Kajiyama called "The Vowel: Its Nature and Structure".
In this book, I can find some diagrams like the one below which purports to be a "four terminal network representation of the production of a any non-nasal sound", but I can't make heads or tails of it.
I'd be grateful for any information that could shed light on how these two disciplines connect. Thanks a lot.