Not speaking

My daughter is almost 16 months, and only really says 1 word which is Mama, and even then its not very often, I've recently had another baby, seperated from my babies dax and moved house and I was told big life changes can sometimes impact development - and its really worried me that she'll never speak........................... I've seen other mums on here saying about their baby talking non-stop; and I'm just a little worried about my daughter not talking. I play nursery rhymes, I always talk to her, we read books, I tell her the name of every item she picks up or is given, we count and I'm going to start taking her to baby/toddler groups to see if being around other babies helps; im just worried shes the only baby her age who doesnt speak??