No speech but good with alphabet and numbers

[Dantiger]

Hi, just wondering if anybody has any experience with this!

So DS has recently turned 3. He is on the asd pathway. He can say hi, bye, and can name some animals and colours if I ask him what they are. Over the past week he can suddenly say numbers 1-10 and the alphabet. If I write them down he is able to say what the number/letter is and knows what comes next. I am wondering how he’s gone from pretty much no speech to being able to do this, super proud and happy!

This is quite common for children with autism - having an interest in labelling and ordering numerals.
But being able to label things, or memorise things is one skill, which is only one part of language development.
It is always lovely to see our dc develop any skill they didn't have previously, but what professionals will be looking for is an ability to use language functionally - to ask for something he wants, to make choices, to respond to questions, to respond to instructions, to continue a 'conversation' by listening to what has just been said and responding appropriately.