Database: world_1
Question: Give the mean life expectancy of countries in which English is not the official language.
SQL:
SELECT avg(LifeExpectancy) FROM country WHERE Name NOT IN (SELECT T1.Name FROM country AS T1 JOIN countrylanguage AS T2 ON T1.Code  =  T2.CountryCode WHERE T2.Language  =  "English" AND T2.IsOfficial  =  "T")