# First, downgrade to ASCII chars (or transliterate if possible)
    @_ = unidecode(@_);

    for( @_ ) {
        s/['"]//gi;
        s/[^a-zA-Z0-9.-]/ /gi;
        s/\s+/_/g;
        s/_-_/-/g;
        s/^_+//g;
        s/_+$//g;
    };
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You say transliterate but you don't actually use transliterate.

        s/['"]//gi;
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Since when do the ' and " characters have both upper and lower case representations?

        tr/'"//d;
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        s/[^a-zA-Z0-9.-]/ /gi;
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Which characters does the /i option affect here?

        tr/a-zA-Z0-9.-/ /c;
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