My mom is a SLP.  It’s not only about muscle training, it’s about understanding how your brain processes auditory input, makes a decision, and sends a vocal output, and if the signals are getting from the brain to the muscles.

When you have a great deal of experience in a field like that you can make a screening assessment pretty quickly.  She had always pointed out some kids say baby words early and others refuse to talk until one day they come out with perfect diction and complete sentences.

If it really bugs you, you could get your child screened periodically by a SLP without committing to any intensive therapy. Preschool screening here starts at 4 years old and maybe younger than that, it’s federally funded in the school system (Title 1?).  Happens in August IIRC.  And I’m sure you can do it through the medical system as your child is likely too young right now for the school screening.