This well known Irish jig is an example of a double jig.
A double jig is in 6/8 metre and is characterised by quavers (eighth notes) grouped in threes. It is the most common type of Irish jig.
With a range of almost 2 octaves, it's no surprise that this jig is generally played not sung! (The prominence of the fiddle and other traditional Irish instruments in Irish dance music rather than solo singing is another reason this song isn't sung as often as it is played!)
Melodic sequence is a feature in this song. (E.g. mdmsfm-frflsf and d'm'r'd't-tr'd'tl)
This song lends itself to interval work - working on intonation and identifying the intervals. The last line works particularly well with the ascending intervals with high do' as the top note. (l-d' minor 3rd, s-d' perfect 4th, f-d' perfect 5th, m-d' minor 6th). Throughout the song you can also find examples of major 3rds, a perfect octave and a variety of other perfect 4ths!
This famous double jig tune is widely considered to be one of Ireland's most iconic fiddle tunes. There are claims that the melody originally came from the English Folk Song 'Dargason' and counter-claims that it's origins are from 'The Country Courtship'. Others believe that the melody did evolve without the influences of these English folk songs.
These days this tune is considered quintessentially Irish and at times is even used by Scottish dancers when they want to dance to an Irish tune!
This melody is also used for the humorous song 'MacTavish is Dead'.
For more information see: https://www.vithefiddler.com/irish-washerwoman-fiddle-tune-a-day-day-57/