I would agree with you on the flavor text issue (see my above post) were it not for the fact that in the invocation full description it says:
However, upon rereading the feat Dark Speech, and the description of its uses, I find that in the feat, nothing is mentioned about knowing it and speaking it is an evil act. In the description, there are several uses that are evil, but the one most similar, the softening use, is not strictly evil. One could even see the power as the warlock saying shatter in the Dark Speech, and objects shattering due to its power.
However, on the flip side, does using the Words of Creation constitute a good act?
If so, then it logically follows that using the Dark Speech constitutes an evil act.
That statement removes it from being flavor text.... Dark Speech (described in Book of Vile Darkness) ...
However, upon rereading the feat Dark Speech, and the description of its uses, I find that in the feat, nothing is mentioned about knowing it and speaking it is an evil act. In the description, there are several uses that are evil, but the one most similar, the softening use, is not strictly evil. One could even see the power as the warlock saying shatter in the Dark Speech, and objects shattering due to its power.
However, on the flip side, does using the Words of Creation constitute a good act?
If so, then it logically follows that using the Dark Speech constitutes an evil act.