Language skills are usually better in children cared for 1:1 by an adult who talks to them and engages with them. Thats why first horns usually talk earlier, all things being equal.
Going to nursery doesn't lead to better language skills, some people just insist on believing that the normal, typical, ordinary, average language explosion which naturally happens roughly between 24 and 36 months (give or take - sometimes starting closer to 18 months especially in girls) in typically developing children is "proof" that nursery is beneficial. It's like nursery claiming credit for the age a child walks at. Unless you keep the child strapped down they will walk at the same time whatever you do (unless they have non typical development and need physio or aids or medical intervention).
My dc1 was talking in sentences in two languages by age 2 and she didn't go to any child care. I was a childminder though and had deliberately built up a support network of friends through antenatal classes and baby groups because we had no family support. She was incredibly sociable as a baby and toddler.
Her brothers talked a little later, but still at typical, average ages because of being boys and because they got less 1:1, with chatty DD doing so much of the talking.
So many people give nursery credit for absolutely typical development which happens whether they are with a parent or at nursery, as long as they are talked to and given chances to socialise and play and go out and about and aren't actually neglected.
The only evidence of nurseries benefitting under 3s are in cases where the child is from a very deprived background, where being properly fed, kept clean, warm and dry, and talked to aren't happening due to parents lack of resources (whether financial, educational, time, health or whatever).