CREATE TABLE table_60998 ("Semi-closed initial unstressed vowels" CLOB, "17th c." CLOB, "American" CLOB, "Australian" CLOB, "Examples" CLOB)

For the 17th century entry of , what is Semi-closed initial unstressed vowels?
SELECT "Semi-closed initial unstressed vowels" FROM table_60998 WHERE "17th c." = 'ɐ'
SELECT "Semi-closed initial unstressed vowels" FROM "table_60998" WHERE "17th c." = 'ɐ'