My LO is 15 months it hardly blabber anything. Is it something I should worry?

My older boy which is 8 years old now has speech delay. He spoke his first words at 3 years old. As his motor skills are developing very well I did not worry at that time. But to be safe I brought him to see a PD. And it turns out he has hearing problems that caused the speech delay. He end up having to wear hearing aid. And he attended speech therapy every week. And right now he is slow in his speech but it is much much much better. I suggest you quickly bring your kid to see a PD.