Among the languages used in Baltic Countries, provide the languages which are used by over 80%.
Baltic Countries refers to Region = 'Baltic Countries'; languages which are used by over 80% refers to Percentage > 80;
SELECT T2.Language FROM Country AS T1 INNER JOIN CountryLanguage AS T2 ON T1.Code = T2.CountryCode WHERE T1.Region = 'Baltic Countries' AND T2.Percentage > 80