My 12 year old son who has hypotonia was similar at 19 months. He had a big vocabulary and he also knew the alphabet. One of his favorite books from the time he was 12 months old until he was almost two was a Dr. Seuss alphabet book. I still have pages of it memorized because he wanted me to read it to him all the time, but I don't remember exactly when he first spelled a word. I know at 2 he was spelling several easy words like boy and girl. He read his first easy reader that he hadn't seen before at about 2 1/2 and he could also name words that were spelled out for him so I knew he wasn't just sight reading, yet he was also considered "developmentally delayed" because his weak muscles made it more difficult for him to develop motor skills.
It was sometimes difficult for other people to understand what he was saying when he was 19 months old, but he also acted out things when he spoke so I could usually understand what he was saying. At that age "chocolate milk" sounded more like "gochen meo" but other words he said were easier for other people to understand. I had once worked with a woman with cerebral palsy so I had practice learning to understand her "language" which she called Gailic because her name was Gail. Her intelligence and sense of humor were not affected by her disability so I wondered for a while if my son had mild cerebral palsy, but when he started walking at 18 1/2 months I thought he was okay and the doctors didn't say anything about any delays at his checkups, but they always noticed his vocabulary because he was not shy about talking to them.
Although my son had developmental delays in his motor skills, he didn't get any kind of therapy, but by age 4 he had learned to slow down when he tried to speak and the only letter he still had trouble pronouncing was L. He got teased a little about this so he practiced pronouncing that letter on his own. By 4 1/2, when he joined a children's community musical theater group, he could finally pronounce L's but his musical theater teacher still had to remind him to slow down and enunciate, especially if he was excited.
He turned 12 this month and he has an incredible vocabulary and the gift of gab just like his dad. People assume that he is older because he is tall and is more articulate than a lot of adults, including me. He doesn't have to be reminded to enunciate any more. He just got the part of the mayor in Seussical and he is taller than the girl who will be playing his wife and she is six years older. People assume that he is several years older than he is which is a good thing considering his friends have always been several years older.
