The Voice of the Chain Master eldritch invocation allows a Pact of the Chain warlock to do the following (PHB, p. 111):
You can communicate telepathically with your familiar and perceive through your familiar's senses as long as you are on the same plane of existence. Additionally, while perceiving through your familiar's senses, you can also speak through your familiar in your own voice, even if your familiar is normally incapable of speech.
Assume a Warlock has the Raven Queen as Patron (from Unearthed Arcana: Warlock & Wizard).
A Warlock with the Raven Queen patron can use the 6th-level Soul of the Raven feature to merge with the Sentinel Raven, as written:
As a bonus action when your raven is perched on your shoulder, your body merges with your raven’s form. While merged, you become Tiny, you replace your speed with the raven’s, and you can use your action only to Dash, Disengage, Dodge, Help, Hide, or Search. During this time, you gain the benefits of your raven being perched on your shoulder.
Is it possible for a Warlock to communicate/speak through his/her familiar (e.g. a pseudodragon) with Voice of the Chain Master while merged with the Sentinel Raven via Soul of the Raven?