Amethyst queries

SELECT t.id, t.title_english, t.title_language, t.language
FROM (
    SELECT 
        a.id,
        a.title_english,
        a.title_language,
        a.language,
        @rn := IF(@prev = a.title_language, @rn + 1, 1) AS rn,
        @prev := a.title_language AS prev_tl
    FROM amethyst_1 a
    JOIN (
        SELECT title_language
        FROM amethyst_1
        WHERE title_language IS NOT NULL
        GROUP BY title_language
        HAVING COUNT(*) > 1
        ORDER BY COUNT(*) DESC
        LIMIT 10000   -- top X duplicated titles
    ) top_dup 
        ON a.title_language = top_dup.title_language
    CROSS JOIN (SELECT @rn := 0, @prev := '') vars
    ORDER BY a.title_language, a.id
) AS t
WHERE t.rn <= 5       -- first Y rows per duplicated title
ORDER BY t.title_language, t.rn;