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How does Firefox's spell check work?

Firefox Languages
James replied 2 weeks ago
侃々諤々
侃々諤々

I use Firefox in Japanese. Often, when I type Japanese text into an input field, a red wavy underline appears. I know this is the spell-check feature, but I don’t understand the specific criteria it uses to determine whether something is correct or not. Since it doesn’t actually correct the text for me, I’m thinking of turning it off, but before I do, I’d like to understand how this feature works.

For example, even a sentence that seems perfectly fine,

“Apples are delicious.” is flagged as incorrect by this feature. It’s a confusing feature—if I remove the period (.), the underline disappears.

Is this actually useful? It underlines every single sentence.

P.S. I believe the Japanese dictionary is downloaded into Firefox.

I use Firefox in Japanese. Often, when I type Japanese text into an input field, a red wavy underline appears. I know this is the spell-check feature, but I don’t understand the specific criteria it uses to determine whether something is correct or not. Since it doesn’t actually correct the text for me, I’m thinking of turning it off, but before I do, I’d like to understand how this feature works. For example, even a sentence that seems perfectly fine, “Apples are delicious.” is flagged as incorrect by this feature. It’s a confusing feature—if I remove the period (.), the underline disappears. Is this actually useful? It underlines every single sentence. P.S. I believe the Japanese dictionary is downloaded into Firefox.

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James
James
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Chosen Solution

https://support.mozilla.org/en-US/kb/how-do-i-use-firefox-spell-checker

Firefox automatically checks the spelling of words that you enter in text boxes. As soon as you finish typing a word, it is checked against the words in the installed dictionary. If the word is not found in the dictionary, it will be underlined in red, as in the following example:

The underlined words means it is not in dictionary so either it is wrong is spelling or because the word is not in dictionary since the dictionaries do not contain all words for that dictionary language. Any word you know is correct you can add it.

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