Your baby follows complex sequences, tests hypotheses (dropping different objects to see if the same thing happens), and engages in early symbolic play — holding a block to their ear like a phone. They understand categories deeply: dogs and cats are different, spoons and forks are both for eating. This categorical thinking is scaffolding for language.
Separation anxiety may be easing or still strong — every baby is different. Cooperative play is emerging: rolling a ball back and forth, taking turns, simple games with rules. According to Zero to Three, limit-testing at this age is normal and a sign of cognitive and social development. They express affection deliberately — hugs, kisses, offering you a toy.
Most babies have 1–3 recognizable words. They understand 50+ words and can follow simple directions. Gestures are plentiful — according to the CDC, using several gestures by 12 months is expected. Proto-conversations are happening with clear communicative intent.