Generally, we recommend NOT correcting a child’s speech during conversation. Instead, YOU repeat it correctly and really enunciate the correct production a couple times. So, if your child says they want a “tootie” instead of “cookie” – you can say “Oh, you want a CooKie – Let’s see what kind of CooKies we have – you love “CooKies” etc. Another example would be: the child says they want to color something “yewow.” YOU repeat “yellow” back correctly in a natural way while highlighting the correct L sound. (e.g., “Yes, the sun would look good yeLLow. I wonder what else would be good yeLLow? Can I have the yeLLow next?”)
Then find a couple short times each day — ideally 5 minutes in the morning and 5 minutes at night — to practice in a drill fashion and expect accurate productions then only. Work with an SLP to know which sounds you should target.
Otherwise you may be correcting all day. This often results in a child becoming reluctant and/or frustrated during conversation.