We just got an email from Virginia Li, of Pathways.org. They have recently completed a new YouTube video and brochure on early communication development, which both cover major milestones and tips for what parents can do to help their infants reach these milestones. The video covers information for the first year (check it out here) and the brochure covers ages zero to three (see here).
This is a fantastic free resource. Thanks so much, Virginia for the heads-up on its completion!