Research has repeatedly shown that learners benefit from multimodal (both visual and auditory) instruction, so using a speech commentary is a great way to engage learners with eLearning. You can choose either to record a human voice (perhaps even your own) or to use Captivate’s Text to Speech (TTS) feature. This simulates human speech based on text that you provide as Slide Notes.
The appeal of TTS is that it is very quick and easy to use, you always get perfect sound quality (though not necessarily a perfect delivery of the words), and it is always available and entirely consistent. Contrast that with a real human voice provider who may be off sick the day you need to make an urgent and critical update. The savings offered by TTS can be significant, as I find the recording of voice narration to be one of the most time-consuming tasks of the Captivate project development life cycle. However, do be aware that the results are never as natural and convincing as a real human voice.
My tip is to use TTS for early review versions of your projects. Using TTS means that it is very quick and easy to create and edit the speech. When you have received all your review comments, and you are confident that the script will not need to change further, then you can record the final script using a human voice.
If you use Captivate 5.x, there are two alternative sets of voices that you can freely download for use with Adobe Captivate. The two sets of voices are sourced from two different voice technology companies: NeoSpeech and Loquendo. It is important to know this, because the facilities provided for controlling the pitch, speed, and pronunciation of the voices are different for the two companies.
NeoSpeech provides two voices: Paul and Kate, both of whom have American accents. These are the same two voices that were available in Captivate 4.0. Loquendo provides three voices: Simon (British accent), Juliette (for French language), and Stefan (for German language). Don’t attempt to use a voice to speak a language for which it was not intended — the results are completely unintelligible! In addition, if you have other voices installed on your computer (Microsoft Anna, for example), these will be made available to you for use within Captivate 5.x. So it is possible to purchase and make use of a range of voices for other accents and languages within Captivate 5.x.
If you use either of the NeoSpeech voices, then you can embed VTML tags within the Slide Notes text to indicate pauses, and to control the speed and pitch of delivery. You can also control the pronunciation of specific words by using the User Dictionary Editor. This is a file called UserDictEng.exe, which you will find buried in the following folders within your Captivate 5.x installation folder:
There are instructions for working with the User Dictionary Editor in this Adobe blog post. The article refers to Captivate 4.0, but the instructions remain the same for Captivate 5.x.
If you use the Loquendo voices, then a pronunciation dictionary is not available. However, you can still control the delivery by including Loquendo tags (not the same as VTML tags) within the script.
Please note that if you are using either VTML or Loquendo tags within your Slide Notes, and you also want to display Slides Notes as Closed Captioning (subtitles), then you will need to add two sets of Slide Notes for each slide: one with tags, and one without. You can indicate for each Slide Note whether it is to be used for TTS or for Closed Captioning (see the screenshot below).
In summary, Text to Speech is a useful tool for prototyping and for creating voiceovers very quickly and easily. There is some scope for controlling the pace and intonation of delivery, but (in my opinion) the technology has still not reached the point of providing a truly convincing alternative to a real human voice for final delivery of polished eLearning.