For truly anonymous, deniable communication …
Create a number of fake email identities— probably best with with a service like Protonmail, but it needn’t necessarily be and, above all, they each need to be with a different service (which will limit how many such providers you can use anway).
Choose a code you will use with the people you communicate with — every fifth word is part of the real message … or whatever you come up with between you.
Now go to a number of internet/cyber-cafes and post your message spread across Usenet groups — one part per identity, one part per Usenet group, one part per internet/cyber-cafe. Change the specific order every so often. Change the specific groups every once in a while.
Keep the message style pertinent to the group and thread — don’t start discussing cooking recipes in a group concerned with computing topics … nor your accounts in a thread on football (well, you shouldn’t be discussing your accounts in any Usenet group really, but you get the point).
Limit the connections between the identities you use and those with whom you communicate: keep the connections fixed, with the same two or three individuals replying to the same two or three others — not all of your identities replying to all the others (which makes it easy to discern the connections between seemingly unrelated threads and seemingly unrelated people).
Randomise your reply pattern: sometimes you reply to a previous message thread … sometimes you start a new, unrelated thread — your contacts know what identities they are looking for messages from, so they don’t all need to be in the same thread every time (again, this makes it harder to discern the pattern of communication, as messages are spread over multiple threads and need to be pieced together by third parties who don’t know where the pieces are to be found).
Update your identities periodically — the people you are communicating with know what the code is and will recognise a real message when they decode it (all they have to do is to try and decode every message they see in a thread and when one reveals a hidden message, they’ll know this is a new identity to follow).
BTW …
Gini est allée en Grande Bretagne.
El Tejón está en Irlanda.
