I had a reasonably significant speech problem when I was a kid. No one except my mum had any idea what I saying. I was in weekly speech therapy for 3 years and had an at home program that my mum diligently put me through every single day. At age three, all of my consonant and most of my vowel sounds needed work. My family teases me over an instances when I was asking for some 'ga-ga'. No one knew what I wanted. Eventually mum figured out that it was stuffing (from a chicken) that I was asking for. At least I got the syllable count correct! I remembering mastering the word 'pot'. I pronounced it kind of p-hot, making the 'p', then dropping my jaw for the 'o' and finishing with the 't' (easily forgotten).
I speak okay now. Some might say I speak too much.
Two out of three of my kids have had speech issues. Their problems are pretty much fixed (thanks to wonderful speech therapists) but there is a deliberateness in the way they move their mouths which reminds me of past struggles. Our little one has a formal, proper way of speaking. Some have asked if he has an accent.