Unsure. I'm not sure if baby talk impedes the acquisition of normal language. However, there is no advantage to baby talk, and children do learn by imitation. There do appear to be advantages to learning if you include children in conversations that "stretch" their minds. Also, it is clearly important to talk to your children...A lot. More is better in regards to learning.
Baby talk is fine. Baby talk is a normal and good way to engage with an infant or young child who is not yet talking. At about 18 months when the child is imitating your speech and able to do so accurately, you want to make sure you are pronouncing words correctly but even then we adults speak very differently to young children with a sing song voice and a lot of repetition. This comes naturally to most adults.