This text comes from The Book of Scottish Song, edited by Alexander Whitelaw, a historical songbook transcribed on Wikisource and reproduced from the pinned revision linked below.
I kenna what's come ower him,
He's no the lad he used to be;
I kenna what's come ower him,
The blythe blink has left his e'e.
He wanders dowie by himsel',
Alang the burn and through the glen;
His secret grief he winna tell—
I wish that he would smile again.
There was a time—alake the day!
Ae word o' mine could mak' him glad;
But noo, at every word I say,
I think he only looks mair sad.
The last time I gaed to the fair,
Wi' Willie o' the birken-cleugh,
Like walkin' ghost he met us there—
And sic a storm was on his broo!
I'm wae to see the chiel sae glum,
Sae dismal-like frae morn to e'en:
Than sic a cast as this had come,
I'd rather Willie ne'er ha'e seen.
I kenna what's come ower him,
He's no the lad he used to be;
I kenna what's come ower him—
The blythe blink has left his e'e.