Sign language - are the signs international?

Early Learning Teaching Your Child - Signing, Speaking, Languages
1

Hi,

I have one question to sign language users:
In introducing new languages to a child, a sign language offers a really handy, funny and interactive “bridging tool”.
While collecting materials I came across one problem: A same word can be signed differently in ASL and AustralianSL e.g. daddy.
I was thinking to use BST videos and australian flash cards, but they seem to be incompatible.
Are the diferences really big, or it is just a small portion? I am worry to get my child confused combining different recources…

2

American Sign Language (ASL) is different for other countries but there are similarities. My sister was able to communicate with a French couple via sign lanuage with some differences. I am by no means an expert, you might want to compare the signs for each country and use the ones that are the same first.

I am just starting to sign milk to my 2.5 month old son each time I offer him a bottle. I know that the sign for milk in ASL looks like milking a cow but other countries tap the breast for milk as if breastfeeding.