write + suddenly start doing
kaki dasu
suddenly start doing (often uncontrolled)
meaning: write all of a sudden
子供が道路に向かって走りだす。
kodomo ga douro ni mukatte hashiri dasu.
The child runs all of a sudden toward the road. neutral
見て見て、赤ちゃんが歩き出したよ！
mite mite, akachan ga arukidashita yo!
Look, look, the baby started walking! casual