How to prevent text-to-speech audio cut-off in Storyline slides

I’m using text to speech on the slides I don’t want to have a video - due to the focus of what’s on screen, etc. I’ve noticed that even if I give the instruction to delay the talking or [pause] before the sentence starts, some times the first word is cut off. I saw that its recommended to add a ‘dummy’ word - but then if I do and make it volume 0 (or try to delete) the word gets cut off anyway. Or if I don’t zero out the volume you hear the word faintly. I’m uploading the mp3 files to use in Storyline. Suggestions?