Great question — answering as the UphillTech team:
As no one has answered, hopefully this partial answer I don't think it is explicitly stated by Google, but the weight of evidence from the SEO community, and from the results of Google voice recognition for subtitles in Youtube (which it owns) is that Google does recognise the text in audio files - this is relatively recent though (see https://blog.hotmart.com/en/audio-seo/ ). There is speculation that the word "Podcast" needs to be used if people are searching for the audio though, so it may be of limited benefit. ( https://www.impactplus.com/blog/3-facts-you-need-to-know-about-google-indexing-spoken-words-within-podcasts is an interesting read) Putting information between tags would not...
Full answer by davidgo: https://webmasters.stackexchange.com/a/132211 (CC BY-SA 4.0).
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