Are user defined articulations limited to a certain amount (like Sibelius) or unlimitied (like Finale)?
Although it is most likely that in a common situation the given articulations are fair enough there are quite some situations that require user-defined articulations, -
Edu-material, analysis, advanced notation, - and, of course, playback when multible similar signs are needed to trigger differing sounds (I counted 5 different staccatos and at least 4 different tenutos in my VSL setup)
In Dorico, an articulation is one of only eight specific things (staccato, staccatissimo, accent, tenuto, staccato-tenuto, marcato, stress, unstress). If you need different playback for staccato for the same instrument under different circumstances, off the top of my head I’m not sure exactly how that will be achieved. You cannot define custom articulations at all, because we define articulations in a very narrow way. This allows us to handle the positioning of articulations versus slurs, tuplets, and so on, in a clever way.
The more general concept is of “playing techniques”, which will still be able to be positioned relative to noteheads and stems if needed, as articulations are, but which will allow more flexibility in terms of their appearance and playback effect. You could certainly define a new playing technique that looks like a staccato but which does something specific in playback, but it won’t be positioned like a regular staccato articulation.
Daniel, are you planning to expand the articulations concept to include editorial versions in brackets or parenthesis (whether they are defined as ligatures in the font or not), or are you anticipating that these will fall in under playing techniques in the future?
I hope that you will be able to add parentheses or brackets to the existing articulations at some point, though probably not in the very first version. You add parentheses to dynamics and tempo markings, for example, using the Properties panel, so this is also the plan for articulations, and indeed other things like noteheads.
Okay, I see… I guess there are probably some tricks to archive those needed thing. Most of these signs will be placed above staff and notes such like tuning markings for the common alterating tuning (ie. C in F major versus C in G minor), kids symbols in EDU, analysis markings.
For the playback one could trigger the wanted sounds with a combination of ie. staccato and a symbol/sign set as you have mentioned in your answer being that Xmaps are involved.
But this guides me straight forward to another question about show/hide which I will post in another thread.
Thanks for your answer… 
One last question: What about combinations of articulations? In the common musical language a short accent has no effect to the duration of the note (see Mahler, Schostakovic, Schoenberg…).
If you need both a short accent and a shortened duration you will need to combine a short accent with a staccato point.
Would this be possible?
Yes, you will be able to define combinations of articulations and playing techniques to trigger different playback effects (at some point!).
Yes, you will be able to define combinations of articulations and playing techniques to trigger different playback effects (at some point!).
Is this option already implemented and how do I assign the right playback effect. I just want to combine staccato and accent …
Yes, it’s already possible. In the Expression Maps dialog, when you add a new switch, use Ctrl+click to select both Accent and Staccato from the list.