Why "enough for to fill" instead of "enough to fill" in this sentence?

"I drank enough drink for to fill Galway Bay". This is from an old Irish drinking song called "Drink it up, men", by the Dubliners. https://www.youtube.com/watch?v=niOHxjdKQ-c

My question is:

• Is it a dated construction in Irish English?
• Is it current usage somewhere in Ireland?
• Is it (and has it always been) ungrammatical?

I've edited the title.

Solution 1:

This for is the complementizer which arose during the transition from Old to Middle English and at one time was widely used with all sorts of infinitive clauses. Here are some examples from OED 1, s.v.For, 11., with my own modernised spelling:

1397 Rolls of Parliament It was my meaning and my weening for to have do the best for his person and for his estate.
1523 Coverdale He maketh too much haste for to be rich.
1748 Washington You must ride round the back of the mountain for to get below them.

The use began to contract in Early Modern English, and in Present-day Standard English (whatever that is) it is almost entirely restricted to clauses with an explicit subject; clauses in complement position are found mostly with specific verbs expressing commands and desires (positive and negative):

For him to say that would be unwise.
I would hate for him to say that.

But the broader use has lingered in dialect.

Solution 2:

To counteract the notion some readers may be getting that "for to" usage is limited to a subset of Irish folk music, I note that it also appears in various subsets of American folk music. Here for example, is segment of the folk song "Oh, Susannah":

I come from Alabama/With a banjo on my knee/I'm going to Louisiana,/My true love for to see.

And from "Polly Wolly Doodle":

Oh I went down South for to see my Sal/Sing polly wolly doodle all the day/My Sal, she is a spunky gal/Sing polly wolly doodle all the day./Fare thee well, fare the well,/Fare thee well my fairy fay/For I'm going to Louisiana for to see my Susyanna/Sing polly wolly doodle all the day.

And of course one of the most popular spirituals of all time, "Swing Low, Sweet Chariot":

I looked over Jordan, and what did I see/Coming for to carry me home/A band of angels coming after me/Coming for to carry me home/Swing low, sweet chariot/Coming for to carry me home/Swing low, sweet chariot/Coming for to carry me home

And in "Can the Circle Be Unbroken" as sung by Kristin Hersh (formerly of Throwing Muses):

I was standing by the window/On a dark and cloudy day/When I saw the hearse come rolling/For to take my mother away

And in the state song of Kentucky, Stephen Foster's "My Old Kentucky Home":

A few more days for to tote the weary load,/No matter, 'twill never be light;/A few more days till we totter on the road,/Then my old Kentucky home, goodnight.

And in the less well known but poignant "Wild Bill Jones":

I went out on one day, just walking around,/When I met up with that Wild Bill Jones,/He was walking and talking with my own true love,/And I bid him for to leave her alone.

And in the equally obscure "Ballad of Cole Younger":

An' again we saddled our horses back up north for to go,/To that God-forsaken country that they call Minnesoto,/I had my eye on the Northfield Bank when brother Bob did say,/Oh Cole, if you undertake that job you sure will rue the day.

It also occasionally appears in more recent songs. From Bob Dylan, "Mr. Tambourine Man" (1964):

Take me on a trip upon your magic swirlin’ ship/My senses have been stripped, my hands can’t feel to grip/My toes too numb to step/Wait only for my boot heels to be wanderin’/I’m ready to go anywhere, I’m ready for to fade/Into my own parade, cast your dancing spell my way/I promise to go under it

Here, as in "Drink It Up, Men," the for provides a necessary short syllable in the song's meter, which puts three shorts between each pair of longs.

Other nontraditional songs with "for to" in the lyrics include "Song of the Shrimp" (an Elvis Presley number):

Goodbye, mama shrimp, papa, shake my hand/Here come the shrimper for to take me to Louisian'

And Pere Ubu, "Love Song":

My eyes are growin' tentacles for to grab you./My eyes are growin' hand grenades for to have you./My eyes are growin' tentacles for to grab you./I live in a house without any windows.

In fact, the main place where you don't hear "for to VERB" is in the everyday speech of practically anyone.