I tried four different packs:
* *thunderbird-i18n-en-US*
* *thunderbird-i18n-en-GB*
* *thunderbird-i18n-pt-BR*
* *thunderbird-i18n-ru*
It did not work. I tried launching thunderbird with --UILocale set to a different locale (matching the i18n packs installed) and still nothing shows up.
The only line that shows up in console when launching in it is this:
`[calBackendLoader] Using Thunderbird's builtin libical backend`
I understand something is wrong with my system, but I can't pinpoint what it is. For more info, here is my fontconfig config file:
```
<?xml version='1.0'?>
<!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
<fontconfig>
<alias>
<family>serif</family>
<prefer><family>Liberation Serif</family></prefer>
</alias>
<alias>
<family>sans-serif</family>
<prefer><family>Liberation Sans</family></prefer>
</alias>
<alias>
<family>monospace</family>
<prefer><family>Fantasque Sans Mono</family></prefer>
</alias>
</fontconfig>
```
Yes, I tried removing the profile many times and it didn't work. I tried even launching thunderbird with a fresh profile with the --UIProfile flag. It also did not work.
I also tried altering, and even removing, my fontconfig file and it seems to have no effect on it.
Yes, I tried using `LANG=C` and it did not work.
I did run thunderbird using `strace` and I copied over all search matches to "font" (and a little bit around it to provide context): [here](https://ghostbin.com/paste/524gk).
Unfortunately, I couldn't figure out what was the problem behind this, so I backed up my data and did a full reinstall of the system. It works as intended now. Not sure why it was that way before.
With that said, I apologize for this. I'm closing this issue. Thanks in advance for the help.