My son was the same at his 2 year review but health visitor wasn't concerned because she could see for herself how much he understood and followed things being said. 2 months later he has a huge collection of words and is starting to put them together. Just keep encouraging the words he does say even if they're not quite right and push him to use them and that understanding of words will soon turn to bossing you about and giving you attitude 🤣
Is he babbling? It may very well be he is saying more just not pronouncing it correctly, that’s what was happening with my son
My little boy's speech didn't start properly until after he was 2, which is quite normal.