20 month old hitting/biting help

[kittlesticks]

Hi all
Any suggestions on how to deal with my 20 month old DD's hitting and biting? We have a 4 year old DS who bears the brunt of it. We do time out but she constantly gets up (literally instantly gets up) laughing, so returning her to time out has become a game.
We never had this with our eldest (looking back of course we were extremely lucky!) but I'm a bit lost on how to show her that it's wrong when her language and understanding isn't there.
Advice welcome, I know she's only little but I'm keen on healthy boundaries!

Personally I think a 20 month old wouldn't understand the concept of time out for it to really work. I should also say I don't use timeout as I prefer other methods so that may cloud my thinking.

I have a non verbal hitter the same age and hold his arm firmly and stay sternly "no hitting". If they hit to get a toy then take the toy away from them. Then try to reinforce kind hands wherever you can. Playing with cuddly toys, animals etc. Using kind hands to stroke them. There are also some books you can get on kind hands.

I also have an older child and always try to explain that the toddler doesn't mean it and that they are feeling angry because they can't communicate, we then talk about how hard it must be not to be able to talk properly. I really don't want my older child to have resentment or anger towards the little one.

Thank you! Books are a good idea as she is a big fan. DS knows she doesn't mean it but I do think it's grating on him. Might stop time out for now then if she's just too little.

Time out at 20 months does make me giggle (although I actually don't believe in it at all so you might not want to listen to me)

It's easy just tell the 20 month old no and remove from situation. Repeat what probably feels like a thousand times a day but be consistent. They will work it out

My rationale for trying time out is that's what we do for 4 year old and I thought unless we were consistent he would be thrown off too.
Right will switch tactic!