When should "Mummy" & "Daddy" fit into the first words game?

My understanding is "normal" speech development is to have 10 words by 18 months old (though some children are scraping that many words and still talk fine).

My little one is 16 months and has more than 10 words now and things seem to be going well but he still doesn't call us Mummy & Daddy. Is that normal? Would you expect Mummy & Daddy to be within the first 10-20 words?

What concerns me is that his older brother said over 100 words at 18 months and could say Mummy & Daddy but in hindsight we realised he never called us Mummy & Daddy, he just repeated the words from books. The tonight his little brother said Mummy for the first time... then followed it with "Hug", reciting from the book "Hug". Shouldn't he be calling me Mummy now that he can say it?

From memory mum-mum and dad-dad were some of DS's first words, he used dad in context from nearly the beginning, ie he would see DH and say "dad-dad, or dae-dae!" but with me, he tended to only use mum-mum when he was old enough to want me for something, say if I was in another room, he would call me. But if he just wanted something like milk, he would just come to me and say milk (or throw a cup at me lol!) KWIM?
Actually saying mummy and daddy, didnt happen for a while.

ETA, this all happened at about 12 months (from memory) but then his speech regressed and he has recently been diagnosed as having speech delay, but is progressing well.

Not sure of the guidelines but all of mine have started with dad and then mum. Dd3 is 15months old and says about 20 words. She calls DH and I mum and dad and refers to her siblings by their name. She will say poppy and Mema and call them by they name to get their attention. She says please for things and when you give her things. She also know words to songs. Everyone after dd1 talked well said that she would talk for the babies but it's the opposite here. My kids don't shut up :)

BUT

Dd3 wAs so slow at other things. She still only has four teeth!

They can't be quick/good at everything :)

I know some will be slower at speech but it's the context of what he's saying (or not) that bothers me. He is using a lot more power words than our older son did (no, up, off etc) so that's great social communication, but to not be using any of our names by now seems to be a red flag.

****.

Of you gave him something and said 'for dad' would he give it to your DH?

If I meant not of..... Silly fat fingers

Yes. He has good receptive language.

So that's promising isn't it?

He's doing heaps of awesome things but I hope he starts saying our names soon, or else I guess I'll talk to our doctor about it at his 18 month check up.

Marley will only use our names if she wants something...to get our attention. She is almost 14 months old now. She has no other words, but communicates very well and understands exceptionally well too. She is very expressive but is much slower than Charlotte was with speech.
If you are concerned I would speak with your paed, but I am trying not to worry until she is 2. I remember Charlotte had a very significant language leap when she turned 2.

My DD says Mummy and Daddy, but sometimes i get called Daddy and DH gets Mummy. I don't know what is 'normal' though.

I can't remember how old DS was when he started saying mummy and daddy, but he could definitely say them a few months before he began using them in context properly, as in calling to me from another room etc.

I would think that if his receptive language is good then you shouldn't worry too much, but maybe bring it up at his next check up if you're still concerned.

We were both called Daddy until quite recently.....I would say he was nearly two before I got Mummy in context and even now he sometimes gets them mixed up at 2 years 2 months! All very normal I think......