奇怪的 ubuntu locale error on Perl

First of all, I encountered the following error message when trying to run my environment .
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perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
        LANGUAGE = (unset),
        LC_ALL = (unset),
        LC_PAPER = "zh_TW.UTF-8",
        LC_ADDRESS = "zh_TW.UTF-8",
        LC_MONETARY = "zh_TW.UTF-8",
        LC_NUMERIC = "zh_TW.UTF-8",
        LC_TELEPHONE = "zh_TW.UTF-8",
        LC_IDENTIFICATION = "zh_TW.UTF-8",
        LC_MEASUREMENT = "zh_TW.UTF-8",
        LC_CTYPE = "C",
        LC_TIME = "zh_TW.UTF-8",
        LC_NAME = "zh_TW.UTF-8",
        LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").
===========================================
This is very confusing. Someone on ubuntu forum helped me :

locale-gen en_US en_US.UTF-8 hu_HU hu_HU.UTF-8 zh_TW zh_TW.UTF-8

dpkg-reconfigure locales