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 Regular past 2 Possessive ‘s’ 3 Present progressive 4 Irregular past 5 Regular third person 6 Regular plural 26-48 25-46 27-33 28-50 19-28 26-40 1 Late III 2 Early I 3 Late I 4 Early III 5 Early II 6 Late II 33-34 31-32 28-30 12-22 22-26 27-28