Rated 2 out of 5 stars

- Doesn't seem to remember at all for me !
- Principle is flawed for many use cases : it should offer to remember the domain, or some rules like : .fr domain by default French, etc etc There are many ways to make it more useful/usable.
- It could try and recognize the language in the mail body or at least in the title ?
The REAL need (and what worked with the venerable Eudora 20 years ago) is simply to look into two selected dictionaries, so there is absolutely nothing to do.
This is a feature that should always have been in TB core.

EDITS :

It actually seems to remember for some contacts but there were reasons that led me to think it didn't remember.

Another issue : when CC'ing, it seems to tag the CCs with the language used, which in my case is definitely not good.
I send emails in English (or French) and typically CC French colleagues who therefore keeps oscillating between Fr and En :-(
-> I would suggest to not record CCs language.

Yet another issue : I use 3 computers (2 desktops and a laptop). I don't think there is an easy way to synchronize the associations. Maybe with a storage on the cloud managed by the extension ? But I don't want to enable this for obvious security reasons.
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I put back 2 stars since I understand some users might find it useful, but it doesn't cut it for me.
I think I should just un-install this extension and keep whining about how Eudora was (20 years ago) so much better than Thunderbird :-( I tried to ask for some obvious enhancement, long ago, but to no avail.

This review is for a previous version of the add-on (1.10.4). 

Hi Bert,
first of all, thanks for trying my addon.

> - Doesn't seem to remember at all for me !

I'm sad that it did not work for you.
I'd like to help you make it work. To help you I need you to follow these steps: https://github.com/beltrachi/automatic_dictionary/blob/master/README.md#bug-reporting

> Principle is flawed for many use cases : it should offer to remember the domain, or some rules like : .fr domain by default French, etc etc There are many ways to make it more useful/usable.

Well it does that in certain way. It's described here: https://github.com/beltrachi/automatic_dictionary#target

>- It could try and recognise the language in the mail body or at least in the title ?

That's another approach that solves another problem, and it's already done. Don't use my extension, you can try this one https://addons.thunderbird.net/en-us/thunderbird/addon/dictionary-switcher/

> The REAL need (and what worked with the venerable Eudora 20 years ago) is simply to look into two selected dictionaries, so there is absolutely nothing to do.
This is a feature that should always have been in TB core.

I may agree on this part. You can enter the Thunderbird community and push for that to happen if you want https://www.thunderbird.net/en-US/get-involved/