Text-to-Speech narration feature

I am wondering why the Text-to-Speech feature does not include a way to "teach" the narrator proper pronunciation for some words or groups of letters. For example, it would be nice to be able to teach the narrator to pronounce API as A P I rather than having to add spaces to text being copied into Storyline. Developing a way for a user to create a drop down list of pronunciations, for example, would result in a huge time-savings when using the Text-to-Speech feature. Additionally, having to write technical terms out phonetically, repeatedly, is frustrating. A tool to teach pronunciation would also alleviate this burden for the user.