Modern, nice emoji picker that you can use to find and select emojis. It will be copied to your clipboard or even directly inserted into the e-mail, when you click on it.
As-you-type phonetic conversion of text from one alphabet to another, as well as transliteration/detransliteration of selected text anywhere within documents. Supports multiple languages and custom transliteration schemes.
CantoFish is a popup Cantonese-English dictionary for Firefox. It contains over 200,000 entries and works with both traditional and simplified Chinese characters. The Yale and Jyutping romanization systems are supported, as well as Mandarin pinyin.
This extension allows you to easily insert accented characters as you type in firefox or thunderbird. It is similar to abctajpu (no longer supported). With the default settings, simply press "e" followed by "\" to insert "é" "a\" to insert "à" etc...