Expression is
much much more broader than speech. Speech is simply expression governing words only (but there are far far more expressions/actions than words). It is definitely not "mostly the same thing".
For example, going and painting a Nazi swastika or hate symbol on someone elses house is not covered under freedom of speech...because its an expression.
Just like yelling fire (knowing there is not a fire) in crowded theatre (intent of causing damage even death by stampede etc)...is no longer just speech since it carries a call for (intended grievous tort) action...it becomes an expression and is no longer pure speech.
Asking/directing someone to specifically commit a crime is again an expression since its a call to action past the speech itself.
Simply saying "don't send boys/girls to school" is just speech (given no action is directed if you simply dont heed the words). There is no harm in the words given there is no call for action. If the guy said "girls that go to school should be <insert criminal action>"...then its no longer just words, its an expression.
There is no absolute freedom of expression possible in civilised society....because literally anything that is an action can be claimed to be an expression (e.g freedom of religion/expression vs death cult argument).
Free speech (with no underlying criminal action posed by it that would move it into expression realm) on the other hand should be enshrined as much as possible, because speech in itself should not be delineated as to what words "offend/harm" and which others do not.
I would recommend you to read the 1st amendment of the US for example and then the details of Schenk vs US case law to get a better understanding of what I am saying here.
We had a bit of a discussion on it just earlier in the forum actually:
https://defence.pk/pdf/threads/indi...nds-woman-in-jail.596683/page-3#post-11098012
@Joe Shearer @VCheng @Gibbs @Cookie Monster @Hamartia Antidote @RabzonKhan @Vibrio @Signalian