New Living Translation
“How long has this been happening?” Jesus asked the boy’s father. He replied, “Since he was a little boy.

American Standard Version
And he asked his father, How long time is it since this hath come unto him? And he said, From a child.

Berean Study Bible
Jesus asked the boy’s father, “How long has this been with him?” “From childhood,” he said.

Douay-Rheims Bible
And he asked his father: How long time is it since this hath happened unto him? But he said: From his infancy:

English Revised Version
And he asked his father, How long time is it since this hath come unto him? And he said, From a child.

King James Bible
And he asked his father, How long is it ago since this came unto him? And he said, Of a child.

World English Bible
He asked his father, "How long has it been since this has come to him?" He said, "From childhood.

Young's Literal Translation
And he questioned his father, 'How long time is it since this came to him?' and he said, 'From childhood,

Mark 9:21 Additional Translations ...