How long did yours use dummy's for
I'm probably not the best person to ask. Mine were around 4y. I knew they needed comfort so I wasn't going to deny that until it was no longer needed. As a result stopping the dummy was really easy and no stress to anyone.
However...
There's a marked difference in the language/dental damage dummies do, according to how you use them.
I established very early on that dummy was only for sleep time. So free use of dummy 0-6months (when mostly life is all about sleep), slowly restricting so that by 12 months the only dummy child has access to is perminantly attached to the sleeping bag (with a ribbon I see on).
So when baby get up, gets out of sleeping bag, no more dummy. When it's naptime, "let's go find your dummy" is enough to get toddler running to bed.
I also have developed fairly deep sleepers by the time they are 12m. So dummy is in child's mouth for probably 10 minutes max, then not used again until the next sleep time.
So while 20 minutes a day with dummy in mouth (lunchtime nap and bedtime) is not as perfect at 0 minutes, I don't really think it's going to have any impact on dental development. It's certainly not stopping language development because child never had dummy when awake.
These will be very different outcomes to a child who has a dummy in their mouth almost all day, every day, for several years. I am one of those mums who judges others when I see a toddler with a dummy in their mouth. Especially when playing, like at a toddler group or similar. Yet my toddler (2y6m) has a dummy. It is contradictory but I justify it that no one ever sees my children with a dummy - they only have it when in their cot, asleep.