Q: Could the Slovak immigrants read?
During the last decades of the Habsburg monarchy, Budapest tried to switch the Kingdom of Hungary's Slovak, German, Romanian, Rusyn, Croatian schools from teaching in their own languages to using Hungarian. Depending on what school they attended, the Slovaks were able to read and write in their own language, or also in Hungarian.
Although the two languages are substantially different, their spelling rules are mutually convertible and match pronunciation very well (for instance, the first sound in the English chip is always spelled č in Slovak and always cs in Hungarian). Those Slovaks who were taught only the Hungarian spelling were generally able to use that capacity to learn to read Slovak texts on their own.
Literacy in 1900
According to the 1900 census, the Slovak majority counties were among those with the highest literacy in the Kingdom – shaded darker and lighter green; modern Slovakia's border is outlined in red in the north-west:
Male literacy, 1900 census, Kingdom of Hungary. Green 90%-80%; light green 80%-70%; yellow 70%-60%; amber 60%-50%; red 50%-40%; purple 40%-30%; blue 30%-20%. (Male literacy by state ranged from over 90% to 60% in the U.S. in 1900.)
Literacy was higher in some towns, including Bratislava and Košice, than in their surrounding counties. In the Slovak majority area, literacy was higher in the counties with a higher percentage of the Lutherans. In addition to Slovak and (or) Hungarian in grade school, those who went to high school (a minority of the population in the 19th century) also learned Latin and usually German.
The Slovak spelling system with its high match between the letters and pronunciation enables the students to read any Slovak text after the 1st grade, which also applies to the students in Slovakia's schools that teach all the subjects in Hungarian. Intellectual curiosity and education then decide to what level of sophistication people take their literacy from there. In simplified terms (see below), the spelling system generates 99% literacy. Under the circumstances, the Slovak Statistical Office does not trace literacy as a separate category, it is seen as subsumed under "education."
The exception are some of those Roma who did not learn Slovak or Hungarian at home, started school without speaking the language of education (no schools teach all the subjects in Romani), and did not manage to learn its spoken as well as written versions at the same time. Some of them may have remained illiterate in Slovak or Hungarian (as well as Romani) although they do not fall under the category of people with no education in the census.
0.36% people said they had "no education" in the 2001 census. The group comprised some old people who should have attended grade school in the Kingdom of Hungary, severely mentally challenged people, and likely pranksters.