* ילד קטן (yeled katan): This is the most literal translation. `ילד (yeled)` means boy, and `קטן (katan)` means small or little. This is a good general option.
* בַּר קטן (bar katan): `בַּר (bar)` means son. This translates more to "little son" and is more appropriate if you're referring to someone's son.
* נער קטן (na'ar katan): `נער (na'ar)` means boy or youth. This implies a slightly older boy than `yeled`.
The best choice depends on the specific situation. For most situations, ילד קטן (yeled katan) is perfectly suitable.