You can use quite a few tricks to get a better voice-over. Do as many of these as you can!
- Avoid words that are too complex: As in all written text, make the extra effort to see if some words and phrases are a bit simpler. When creating the voice-over, the reason for doing this is that the speech synthesis technology often is a lot better at reading out simpler words.
- For compound-word languages – play with a hyphen: In languages that use many compound words – like Swedish – the synthesis engine sometimes will pronounce those words a bit strange. When having to use rather exotic compounds, you can try to add a hyphen between the word parts just when generating. This can sometimes force the synthesis engine to pronounce the words more clearly.
- Don't cut up sentences: Since the synthesis works on a slide-per-slide basis, cutting up sentences over multiple slides works so-so. The speech synthesis will have no connection between the different parts of the sentence, making the reading a bit strange. So try and have complete sentences for every slide if you can.
- Avoid abbreviations and parenthesis as much as possible: Something that can trip up the timing is slides with many abbreviations. So try and keep those to a minimum – this is also good practice for readability in general. Parenthesis is also something that trips the speech engine up a bit. And read further on for a twist on this theme. Also, things like # – which will read out as "hashtag" in many languages, can make the timing a bit uncertain.
- Write company names as words: Many companies demand that their name is spelled in only upper case. If the company name is meant to be read out – like "IKEA" – you want to write it as "Ikea." This means that the synthesis engine views it as a word and reads it. Otherwise, there is a risk that it will read it letter by letter. There are many cases where that is preferred, and then you can leave the name in all upper case. But if you want to make sure it gets read out – change it to a mixed case before generating.
- Try to avoid language mixing: You set your voice-over to one specific language, meaning that it will read everything in that synthesis engine. The different language versions can read things in other languages, but it's not great. So if you have a situation with many borrowed words – widespread with English titles, for example – try and rephrase something in your source language.
- Alternate text for voice-over: You can let your voice-over read something other than the written script using the "Alt Description" in the right panel. When you input text into that text field, the voice-over will use this text instead of the slide text.
- Removing slide text from voice-over: You can also remove all text for a slide (slide text and alternate text) by using the "Ignore all text" checkbox in the "Alt Description" part of the right panel. Doing so will ignore all text in the voice-over version.