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CloseReview for Dictionary Switcher by carlo santucci
Rated 3 out of 5 stars
Quite smart, and it usually works great. I cannot make it work on Thunderbird though (or FossaMail which I now use). It's a 5-star with TB working.
A suggestion: add a "priority switch" for the English language. Some users might usually or always prefer en-GB instead of en-US (or en-AU etc.)
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