What language was the most used in movies released in 2006?
released in 2006 refers to release_year = 2006; the most used language refers to MAX(COUNT(language_id))
SELECT T.language_id FROM ( SELECT T1.language_id, COUNT(T1.language_id) AS num FROM film AS T1 INNER JOIN language AS T2 ON T1.language_id = T2.language_id WHERE STRFTIME('%Y',T1.release_year) = '2006' GROUP BY T1.language_id ) AS T ORDER BY T.num DESC LIMIT 1