Hi Ulf, I would use: ‘Ha le lO yia’ This is pretty easy to recognize as you cycle through the individual syllables. As you play the keyboard you should be able to make out this word as you play successive keys - there is a ‘reset’ button on the right hand side of the PLAY GUI which will start the word from the beginning - This is also available to program via a CC number (default CC31).
I don’t think you need a test project to be honest - The issue is that when you actually plug some notes onto the staff you are using in Dorico and try and playback, nothing really happens. You can see the keys depressing on the PLAY GUI keyboard, so the notes are getting through somehow, but the sound of the choir that you can hear when you are simply playing the keyboard, is no longer there. Something is different between playing the notes on the keyboard and having Dorico play them back - this is the crux of the problem. You can also see in the GUI that PLAY and OPUS for that matter, split the Word-Builder elements onto separate midi channels.
Hope this helps!