This will be more efficient, plus you have control over the ordering it uses to pick a value:
SELECT DISTINCT
FIRST_VALUE(person)
OVER(PARTITION BY language
ORDER BY person)
,language
FROM tableA;
If you really don't care which person is picked for each language, you can omit the ORDER BY clause:
SELECT DISTINCT
FIRST_VALUE(person)
OVER(PARTITION BY language)
,language
FROM tableA;