Matching Pairs Brown’s MLU stagesOnline version Test yourself on Brown’s research on morphological acquisition by matching pairs of morphemes with the month age of mastery. by Som Person 1 Present progressive 2 Possessive ‘s’ 3 Regular third person 4 Regular past 5 Irregular past 6 Regular plural 27-33 19-28 26-48 28-50 25-46 26-40 1 Early III 2 Late I 3 Early I 4 Late III 5 Late II 6 Early II 27-28 33-34 12-22 22-26 28-30 31-32