The author of the text, from Nexmo, discusses their use of text-to-speech in telephony applications and how they can be enhanced with SSML (Speech Synthesis Markup Language) to add expression to the output. They share an example of a Christmas poem that was created using SSML tags to mark up words for emphasis, volume, and pronunciation, allowing them to improve the rhythm and flow of the speech. The author also showcases how they used various SSML tags, such as `<prosody rate="x-slow">`, `<phoneme>`, and `<say-as>`, to achieve specific effects, including slowing down certain words for emphasis and making a word sound like an expletive. By using these techniques, the author demonstrates how SSML can be used to add more personality and expression to text-to-speech outputs.