I don't know much about Ireland but his is how I could characterize Poland and Polish language during 19th century.

1. In 1815 there were around 10–11 million of Poles. Around 2 times more than people in Ireland.
2. Independent Poland wasn't on the map from 1795 till 1918. However between 1807-1815 existed Principality of Warsaw with Polish as main language. It was replaced by the Kingdom of Poland (1815-31), where administration, education and military were using Polish language. Austrian part of Poland had an autonomy from 1867 onwards and adopted Polish language, what caused frictions with Ukrainians. In the Prussian part of Poland education in Polish was systematically limited. Between 1815 and 1846 existed Free City of Kraków - a small Polish republic.
3. Before the Rzeczpospolita was destroyed by her neighbours the Ministry of Education (KEN) was created. The first of it's kind. With it's help hundreds of teachers were educated and Polish textbooks were created. Polish scientific language was nonexistent before that time. Many words coined then are also in use today. Before the partitions in Rzeczpospolita there were universities in: Kraków (from 1364), Wilno (from 1579), Lwów (from 1661/1758) and Zamość (1594–1784). Between 1816 an 1831 there was also a university in Warsaw. Reopened again in 1870 with Russian as the language of lecture.
4. For the nobility, Polish language was the language of prestige and tradition. For others German could been seen as more prestigious (e.g. a botanist Edward Strasburger, born and educated in Poland, published in German). Russian was different in that it wasn't so prestigious and the Russians were Orthodox, while Poles were Catholics. Russians used Cyrillic script, while Poles used Latin based alphabet. Two great rebellions against Russians and their counteractions increased hate towards them. Besides Poland was the richest and most industrialized part of the Russian Empire.
5. Between 1807 and 1815 Samuel Bogumił Linde published his monumental dictionary of Polish language. Outstanding work. The vast majority of it's entries come with quotes and translations to German and other Slavic languages. 19th century was also full of poets like Adam Mickiewicz and Juliusz Słowacki, novelists like Henryk Sienkiewicz (awarded with Nobel prize), composers like Fryderyk Chopin. Between 1859-1868 first multi-tome Polish Encyclopaedia was published. Polish press was active in 18th century and remained such in 19th century. Lucyna Ćwierczakiewiczowa was a writer, journalist and the author of cookery books. She had one of the biggest circulation in that times, greater than aforementioned Mickiewicz and Słowacki.