Average Order of Acquistion of Grammatical Morphemes

This is an area of linguistics I find fascinating. If you have a toddler, listen to his or her developing language carefully. It will follow this general order. If you notice your child using plural words, it means your child has already mastered words ending in -ing. A child can't master #4 until the ones before it are mastered. Also, if a child has mastered #7, it means the ones before it are already mastered even if you haven't noticed it yet. Each language has its own order. Interesting, eh? Here's the order with examples of what each means.

1. present progressive (eating)
2/3. prepositions (in, on)
4. plural (cats, toys)
5. irregular past tense (went, saw)
6. possessive (cat’s, mom’s)
7. copula, uncontractible (I am, she is)
8. articles (the, a)
9. regular past tense (talked, goed)
10. third person present tense, regular (sees, eats)
11. third person present tense, irregular (is, does)
12. auxiliary, uncontractible (am going, is eating)
13. copula, contractible (I’m tired, she’s here)
14. auxiliary, contractible (I’m going, she’s eating)