Brief language development scale (Comparison of English and Japanese):
Language development scale differs in what language the child uses as a mother tongue.
| English | ||
| Approximate age | language skills | skills related to numbers |
| 6~9 months | babble | – |
| 9~18 months | holophrastic stage | – |
| 18~24 months | two-word stage | – |
| 24~30 months | telegraphic stage | count 1~2 |
| 30 months~ | multi-word stage, phonological awareness | count 1~3 |
| 4 years~ | use of a sentence with more than four words | count 1~10 |
| 5 years~ | reading simple letters | count over 10, simple addition and subtraction |
| Japanese | ||
| Approximate age | language skills | skills related to numbers |
| 6~12 months | babble | – |
| 12~24 months | one-word stage | – |
| 24~36 months | two-word stage | count 1~2 |
| 36~48 months | three-word stage | count 1~3 |
| 4 years~ | phonological awareness, use of a sentence with more than four words | count 1~10 |
| 5 years~ | controlling particles, reading simple letters | count over 10, simple addition and subtraction |