1980922 - Translate language recognition error on pdf viewer

Status: UNCONFIRMED

(Firefox :: Translations, defect)

Description

[Haifeng]

Attachment: firefox.png

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Safari/537.36
Firefox for Android

Steps to reproduce:

Use Simplified Chinese（简体中文） as the display language。Open an English PDF document, then highlight a English word and right-click the selected word.

Actual results:

In the menu that appears, there's a high probability that the option "翻译选中内容为英语"（Translate selection to English） will appear.There is a high probability of error only when selecting a single word. If you select multiple words or sentences, it is OK.

Expected results:

The option is "翻译选中内容为中文（简体）"(Translate selection to Chinese(Simplified))

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Firefox::Translations' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Negritas Sergiu, Desktop QA]

Hello! I have tried to reproduce the issue with firefox 143.0a1(2025-08-12) on Ubuntu 22.04 and Windows 10, unfortunately I wasn't able to reproduce the issue.
Could you please answer the following questions in order to further investigate this issue

1. Does this issue happen with a new profile? Here is a link on how to create one: https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

Comment 3

[Haifeng]

HI.
I did not create any Profile. The issue occurs when I use Simplified Chinese as the UI display language. If I switch the display language to English and restart the browser, the issue is gone.

Comment 4

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:epavlov, could you have a look please?

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