A common suggestion that I make for toddlers with a developmental delay, particularly with language skills, is to go to daycare, preschool, or Mother's Day Out (MDO) for at least 2 days a week. I make this suggestion especially for children who don't have siblings or who are the oldest child. Children need to be around other children their age which helps them learn how to play, talk, and share. Having said that, there is a difference between how kids thrive in good child care and low quality child care. Here is a link to an interesting study that evaluated how children progressed with development in different types of daycare:
Study of Early Child Care and Youth Development (SECCYD)
I realize that not everyone wants to send their child to a facility such as MDO or daycare, or maybe they want to but can't afford it. In that case, I help the parents brainstorm other ways to be around children, such as play groups, library story time/ craft time (FREE!!!), church activities, neighborhood groups, and other public places that may have free admission at least once per week such as an interactive children's museum. My subdivision has a monthly newsletter and within it, dates/times are identified for Mom's groups, play groups, and special events. It may not be the same teacher and peers each time like a daycare or preschool would be, but at least there is socialization among the children.