What are common questions about developmental stages and milestones?

Sitting, walking. The most common questions about a baby's development have to do with their motor development and expressive abilities. Parents want to know when a baby will sit (around 6 months) walk (around 9-12 months) and talk (saying "mama" and "papa" close to when they are one year old).
Walking, speaking. Is you baby rolling over from front to back at 4 months? Is your baby sitting up at 6 months? Is your baby eating from a spoon at 6 months? Is your baby babbling at 6 months? Is your baby crawling at 9 months? Is your baby walking with or without support at 12 months? Is your baby saying "mama", "dada" at 12 months? Is your baby drinking from a sippy cup at 12 months?