Twelve lessons on the streaming-specific audio engineering tasks: how to comply with EBU R128 / ATSC A/85 loudness, how to ship multi-language audio and descriptive-audio tracks, how to design audio-only ABR ladders that don't waste bandwidth, the encoder mechanics behind HLS audio segments and DASH AdaptationSets, the role of the audio renditions list in CMAF, and how to debug the lip-sync problems that surface only after content ships through a CDN.