Voice is sound production. Speech is what ultimately comes out the mouth after the sound is modified by the tight coordination among the throat muscles, palate, tongue, lips, teeth, etc. An example of a voice problem is hoarseness. A speech problem would be stuttering, or nasal-sounding words, or mumbling.
Speech researcher Christine Ericsdotter precisely captured the intricate movements of the tongue, lips, pharynx and jaw during speech using a rapid-fire X-ray.
Check out the video she created here!
This link provides a cartoon animation of how each sound in the English language is produced from an anatomical standpoint.
