William Haliday
William Haliday (1788–1812) was an Irish language enthusiast. He sometimes used a galicized version of his name William O'Hara, in some documents his surname is misspelt "Halliday".
The son of a Dublin tradesman, he was born around 1788, he studied the Irish language, and produced a grammar of it aged 19 under another the assumed name, Edmund O'Connell (signing "E.O'C"). He trained as a solicitor. 
In 1808 he assisted Edward O'Reilly, Dr. John Langian, and Father Paul'O'Brien (Professor of Irish at Maynooth College) in founding the Gaelic Society of Dublin, an effort to save the Irish language.

He died aged 24, on 26 October 1812 and is buried in Taney Parish, graveyard, Dundrum, with an inscription on his tomb by Dr. Lanigan. His younger brother was the historian Charles Haliday.
Q5344673
Edward O'Reilly
PER
Q1587220
John Langian
PER
Q18733798
Paul'O'Brien
PER
Q4556206
Maynooth College
ORG
Q9142
Irish language
Concept
Q7682571
Taney Parish
LOC
Q5078698
Charles Haliday
PER
Q18672769
William Haliday
PER
1788-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
1788
DATE
1808-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
1808
DATE
1812-10-26T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
26 October 1812
DATE
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1788
NUMBER
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1812
NUMBER
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19
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24
NUMBER
date of birth
sibling