Write SQL query to solve given problem: Among the countries that use Italian as their language, what is the percentage of republic countries?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT CAST(SUM(CASE WHEN T2.GovernmentForm = 'Republic' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(*) FROM CountryLanguage AS T1 INNER JOIN Country AS T2 ON T1.CountryCode = T2.Code WHERE T1.Language = 'Italian'