That's normal for his age. I had terrible trouble with th and d sounds till my grade 1 reading teacher taught me how to say them distinctly and my cousin just gave up on "Jerry" and called me "Silly" because of his early problems with "J" and "r". Somewhat of a profit he was.
Once he gets into reading circles with the teacher and some coaching he'll grow out of it. If he didn't talk at all it would be a worry but from the videos you've shared he's more than happy to communicate.
That's normal for his age. I had terrible trouble with th and d sounds till my grade 1 reading teacher taught me how to say them distinctly and my cousin just gave up on "Jerry" and called me "Silly" because of his early problems with "J" and "r". Somewhat of a profit he was.
Once he gets into reading circles with the teacher and some coaching he'll grow out of it. If he didn't talk at all it would be a worry but from the videos you've shared he's more than happy to communicate.