While the Irish labored for independence in the decades leading to the 1916 Rising, they also made significant efforts to assert the repressed Irish culture. The Irish people formed various associations dedicated to Ireland’s language, literature, culture, and political independence.
In the 1890s, the Gaelic League was established to encourage the use of the Irish Gaelic language.  The League published its own journal, written almost completely in Gaelic, with Irish songs, vocabulary words, and other items of interest. 
Gaelic League. Book, "Report of the Gaelic League: For the Year Ended 30th September, 1894," 1895. Dublin: Dollard Printinghouse, 1895. [Digital Library]
Pearse, Padraic. Suantraidhe Agus Goltraidhe / Pádraic Mac Piarais. Baile atha cliath. [Dublin]: The Irish Review, 1914. [Digital Library]
The founding of the Sinn Féin party in 1905 by Arthur Griffith revealed the Irish political commitment to self-sufficiency and separation from England in culture and economics.  Ireland’s independence was increasingly debated as the question of granting Ireland its own parliament, otherwise known as Home Rule, came up for debate.  The concept of Home Rule was not universally supported; many in the northern province of Ulster sharply opposed Home Rule. 
Griffith, Arthur. Pamphlet, "The Sinn Fein Policy," [1907?]. Dublin: J. Duffy, 1907. [Digital Library]
Ó Síothcháin, Seaghán. Pamphlet, "Constitutionalism and Sinn Fein," [n.d.]. Dublin: An Chomhairle Náisiúnta. [Digital Library]
Yeats, William B. Sinn Fein. Clan-na-Gael Dramatic Association Produces W. B. Yeats' Successful Plays Cathleen Ni Hoolihan and A Pot of Broth, [1904?]. Clan-na-Gael, 1904. [Digital Library]
Although the English parliament did consider granting Ireland Home Rule, once World War I began in 1914, the matter was postponed until after the war.  Relying on the hope of future Home Rule, Irish nationalists did serve with the British Army in the war.  Other Irishmen who preferred continuing the union with England also served in the Great War, participating in key battles, including the Battle of the Somme in July of 1916. 
Samuels, Arthur Warren. Home Rule: Fenian Home Rule: Home Rule All Round: Devolution: What Do They Mean? Dublin: Hodges, Figgis & Co, 1911. [Hathi Trust]
Samuels, Arthur Purefoy Irwin. With the Ulster Division in France: A Story of the 11th Battalion Royal Irish Rifles (South Antrim Volunteers), From Bordon to Thiepval, in Four Parts, Including Photographs and Maps / By A.P.I.S. and D.G.S. Belfast : William Mullan & Son, 1918. [Digital Library]
“Begging for Irish Recruits,” The Gaelic American - Vol. XII, No. 27, July 3, 1915, Whole Number 616. New York [N.Y.] : Gaelic American Pub. Co, 1915, 2. [Digital Library]
However, some Irish nationalists, especially those belonging to the militant nationalist group, the Irish Volunteers, would not fight for the British.  One such nationalist was Sir Roger Casement, who not only argued against Irish service in the British Army, but also believed a German victory in the Great War would be more beneficial for Ireland than an English victory. 
Casement, Roger. Typescript, "Ireland, Germany and Europe". 1911. [Digital Library]
Photograph, Sir Roger Casement Portrait. [Digital Library]
As World War I raged on, the National Volunteers, an armed Irish nationalist group, arranged for a delivery of rifles at Howth. While the arms were indeed delivered, the Howth gun-running ultimately resulted in the police firing on crowds of Irish men and women who witnessed the confrontation between the Volunteers and the police. 
The Gaelic American - Vol. XI, No. 31, August 1, 1914, Whole Number 568. New York [N.Y.]: Gaelic American Pub. Co, 1914. [Digital Library]
The Gaelic American - Vol. XI, No. 32, August 8, 1914, Whole Number 569. New York [N.Y.] : Gaelic American Pub. Co, 1914. [Digital Library]
1. Blanche Marie Brine, Sinn Fein, An Epitome (Washington, D.C.: Friends of Irish Freedom, National Bureau of Information, 1920), 4, http://digital.library.villanova.edu/Item/vudl%3A136598
4. BBC, “Profiles: Sinn Féin,” Easter 1916: From Home Rule to Independence," September 24, 2014, http://www.bbc.co.uk/history/british/easterrising/profiles/po18.shtml; Padraic Colum, “Sinn Fein and Irish Ireland,” in Padraic Colum, et al., The Irish Rebellion of 1916 and its Martyrs: Erin’s Tragic Easter (New York: The Devin-Adair Company, 1916), 41-43.
5. John F. Boyle, The Irish Rebellion of 1916: A Brief History of the Revolt and Its Suppression (London: Constable and Company Limited, 1916), 22; Colum, “Catholic Emancipation and Agrarian Reform,” in Colum, et al., The Irish Rebellion of 1916 and its Martyrs, 28-29.
8. F. X. Martin, ed., Leaders and Men of the Easter Rising: Dublin 1916 (Ithaca, NY: Cornell University Press, 1967), 179; Charles Townshend, Easter 1916: The Irish Rebellion (Lanham, MD: Ivan R. Dee, 2006), 64.
9. Colum, “Ulster’s Opposition to Home Rule,” in Colum, et al., The Irish Rebellion of 1916 and its Martyrs, 45-49; Martin, ed., Leaders and Men of the Easter Rising, 179; Arthur Purefoy Irwin Samuel, With the Ulster Division in France: A Story of the 11th Battalion Royal Irish Rifles (South Antrim Volunteers), From Bordon to Thiepval, in Four Parts, Including Photographs and Maps / By A.P.I.S. and D.G.S. (Belfast: William Mullan & Son, 1918), 5-6, http://digital.library.villanova.edu/Item/vudl:132801.
The Gaelic Journal, Vol. 1. Dublin: The Gaelic Union, 1882. [Internet Archive]