Roger Casement: I bethought me that a peoples language was a living thing, and that it was a shameful thing for an Irihsman to stand by and see the soul of his coutry being dragged out through his lips. I accordingly gave up my club in London, and devoted the amount of the annual subscription thus saved to a training college in Munster where Irish teachers are perfected in a fuller knowledge of, and a more scientific method of imparting, kitchen Kaffir. (Casement, On the Prosecution of Irish, in Ho. Mackay, The Crime Against Europe, Dublin 1958, p.96; cited in Brian Ó Cuív, Irish Literature and Language, 1845-1921, in William Vaughan, ed., A New History of Ireland, Vol. VI: 1870-1921, OUP 1996, p.410.)
Michael Collins: We only succeeded after we had begun to get back our Irish ways; after we had made a serious effort to speak our own langauge; after we hasd striven again to govern outselves. We can only keep out the enemy and all other enemies by completing that task. The biggest task of all will be the restoration of the language. (Path to Freedom, 1922; new edn. 1968; pp.100-02; cited in Brian Ó Cuív, Irish Literature and Language, 1845-1921, in William Vaughan, ed., A New History of Ireland, Vol. VI: 1870-1921, OUP 1996, p.414.
Pearse on Séadna: The formative influence of Séadna is likely to be great. Some of the distinctive writers have declared that it was the early chapters of Séadna which first taught them to write Irish. Not that they admit themselves mere imitators of Father OLeary, but rather that Séadna showed them how to be themselves. (Review; quoted in Ó Cuív; op. cit., p.420.)
William OBrien made a convincing case for the restoration of Irish at Cork National Society, in 1892. (The Influence of the Irish langauge on Irish national literature and character, Cork, 1892; cited here at 402..
Hyde: I do not think there is much to add to what I have said here, except to observe that it is a national duty - I had almost said a moral one - for all those who speak Irish to speak it to their children also, and to take care that the growing generation shall know it as well as themselves: and in general, that it is the duty of all irish-speakers to use their own language amongst themselves, and on all possible occasions, except where it will not run. For, if we allow one of the finest and richest languages in Europe, which, fifty years ago, was spoken by nearly four millioin Irishmen, to die out without a struggle, it will be an everlasting disgrace and a blighting stigma upon our nationality. (Leabhar Sgeulaigheachta, Dublin 1889, pp.215-18; here p.401.)
Hyde: The inaction of the parliamentarians, though perhaps dimly intelligible, appears, to me at least, both short-sighted and contradictory, for they are attempting to create a nationality with one hand and with the other destroying, or allowing to be destroyed, the very that that would best differentiate and define their nationality. It is a making of bricks without straw. But the non-parliamentarian nationalists, in Ireland at least, appear to be thoroughly in harmony with them on this point. (Beside the fire, London 1890, p.xlv, n.; here p.401.)