In my ongoing Curse of Strahd game,
The question has arisen about what spells a wood elf Way of the Shadow Monk would have access to in the various wereraven forms.
In the humanoid (wood elf) form, all spell casting would be available as normal.
In the hybrid form, most spell casting would still be available, as the hybrid has hands (S), voice (V), and Ki (M). She would just need to remember to bring her fleece after all her gear drops to the ground when changing forms in order to cast minor illusion.
In the raven form, however, most spellcasting would be lost, as the bird does not have hands (S). However, one possible spell retained is darkness, which does not have a Somatic component and which instead is just V, M. The Material components are replaced with Ki, as described in the subclass’ abilities. But can the wereraven’s ability to Mimic serve as the Verbal component?
Mimicry. The wereraven can mimic simple sounds it has heard, such as a person whispering, a baby crying, or an animal chittering. A creature that hears the sounds can tell they are imitations with a successful DC 10 Wisdom (Insight) check.
Is this mimicry close enough to actual sounds that it could serve as the verbal component of the spell? Or is it just imitation sound, not actual ‘sounds of power, and insufficient?
Note that the ‘verbal’ component of spells derives its power not from the words themselves but because the words sound like powerful magical sounds
Most spells require the chanting of mystic words. The words themselves aren’t the source of the spell’s power; rather, the particular combination of sounds, with specific pitch and resonance, sets the threads of magic in motion.
This related question asks whether a wild shaped druid can speak in raven form. On the one hand, actual speaking would require far more verbal repertoire than casting a single action spell. On the other hand, perhaps the ‘sounds of power’ in a spell need to actually really spoken rather than just imitation sounds.
This related question concludes that Kenku can cast spells with verbal components, but it is primarily supported by a Crawford tweet that says "Kenku speak" and ravens seem more limited to me. At the level of mechanics, raven mimicry is detected by a DC-limited Insight check, while Kenku mimicry is detected by a contested Insight vs. Deception check, hinting that the Kenku is more personally in control of their ‘speech’ and some are better than others.