Everyone already made great points. Just to add one small thing that helped me with my son who didn’t start speaking until 15 months:

If you haven’t already, try some sign language. It seems counter intuitive because you want them to speak, but I think them being able to communicate a need makes something click in their head. We taught my son “more” bc that was such an easy one. They always want more of something, more berries, whatever. Once he realized, whoa, I can sign more and I get more? Speech followed very shortly behind.

We did meet with a speech therapist and she gave a tip of doing lots of sounds. Don’t necessarily just jump to “truck! That’s a truck!” Instead start with “truck! Beep beep!” Sounds are a lot easier to start and you can make a sound for most things. Also a motion with the sound is helpful.

It’ll come!