I taught my children to talk by talking to them, and responding to them when they made noises.
I don't think I did teach my children to walk - they just did it. But I provided them with opportunities to develop the skill of walking by letting them see me walk, giving them appropriate flat surfaces to move on, and things (including me) to pull themselves up to standing on and to hold on to until they were confident to walk alone.
I taught my children to eat by giving them milk when they were hungry, and by eating in front of them and giving them access to food so that when they were ready to start eating solids they just helped themselves.
I didn't need to teach my babies to sleep - they slept from their first day. They just didn't sleep in a way that fitted in with my adult sleep patterns. I taught them good sleep hygiene by giving them a safe place to sleep and a consistent bedtime routine based on their body clock, and eventually they anticipated bedtime and went happily to bed and slept through the night at the age when they were developmentally ready to do so without intervention.
I don't think that sleep training is horribly cruel and causes long term damage unless it's done in a very extreme way. For many families, it is the best way to keep everyone happy. But for many other families, responding to a waking baby with cuddles/milk/whatever soothes that particular baby is the best way for that family, and that's just another, slower but equally valid, way of helping a baby to sleep.